Saving Pennies or Dollars is a new semi-regular series on The Simple Dollar, inspired by a great discussion on The Simple Dollar’s Facebook page concerning frugal tactics that might not really save that much money. I’m going to take some of the scenarios described by the readers there and try to break down the numbers to see if the savings is really worth the time invested.

Gayathri writes in: Driving 1mph slower than posted speed limit. Yeah, that’s a myth.

Actually, it’s not a myth. Most cars made in the United States maximize their fuel efficiency at about 55 miles per hour and drop off rapidly above that limit (this is actually from a study – West, B.H., R.N. McGill, J.W. Hodgson, S.S. Sluder, and D.E. Smith, Development and Verification of Light-Duty Modal Emissions and Fuel Consumption Values for Traffic Models, Oak Ridge National Laboratory, Oak Ridge, Tennessee, March 1999).

This means that if you’re tooling along on the interstate at the speed limit of 65 miles per hour and drop that back to 64 miles per hour, you’re actually improving your gas mileage by about 1.5%, according to fueleconomy.gov.

So, let’s work out what that’s really worth.

Let’s say you have a typical car that gets 25 miles per gallon at 55 miles per hour. At 65 miles per hour, it’s going to get roughly 15% worse gas mileage, or 21.25 miles per gallon. If you trim that back to 64 miles per hour, your gas mileage is a bit better – you’ll be getting 21.625 miles per gallon, more or less.

Now, let’s say you’re going on a 400 mile trip on the interstate and that gas is available for $3.25 a gallon.

If you go 65 miles per hour, it will take you 6 hours and 9 minutes to make the trip. You’ll burn through 18.82 gallons of gas, which will cost you $61.17.

If you go 64 miles per hour, it will take you 6 hours and 15 minutes to make the trip, six minutes longer. You’ll burn through 18.5 gallons of gas, which will cost you $60.13.

In short, driving one mile per hour slower will add six minutes to the trip and save you $1.04 in gas. Your savings simply by driving one mile per hour slower is $10.40 per hour. That, of course, is after-tax money.

That figure, as mentioned above, assumes a 25 mile per gallon car, but other mileages have similar savings. It also assumes that you’re slowing down a bit from a speed above 55 miles per hour.

So, should you just go 55 on any road you’re on? I wouldn’t do that. Instead, I’d stick to the posted speed limit and maybe go a mile an hour or two below that in the slower lane on an interstate.

Doing this serves three purposes. One, you’ll put cash in your pocket for the extra time you spent driving. Two, you’ll never get a speeding ticket. Three, you’re sticking more or less with the flow of traffic (going much slower would disrupt that), so you’re not disrupting traffic flow and endangering yourself that way.

The next time I’m rolling along some flat four lane road in southern Iowa, I’ll just set the cruise to a couple of miles per hour below the speed limit and roll along. Sure, I might get there five minutes later, but I know I won’t get pulled over for speeding, I’ve got something entertaining on the radio, and that bit of extra time will put a bit of money straight into my pocket.

Quite often, I get emails from readers asking about the “best” way to purchase a particular car that they want. They have their eye on some new model and want me to essentially tell them that it’s okay to purchase it.

I rarely do. Taking out a loan for a car is only a good move if (a) you’re buying your first or your second car and absolutely need one today to commute to work – and even then, you should be buying a used one or (b) you have enough cash to buy the car you want but you’re offered 0% or extremely low financing, making it cost-effective to take out the loan and then sit on your investment (a pretty rare case, but one we found ourselves in recently).

We fully own both of our automobiles and don’t intend to replace either one of them for years. Of course, we’re slowly saving up for their replacements at a reasonable rate, but we’re not paying interest – interest is working in our favor.

Let’s run the math so that you can see, in real dollars, how much is saved by paying cash. You have no cash at all, but you need wheels. What do you do?

Option 1 – Buying New Now
You go to the dealership and take out a $25,000 loan on a new car. That loan is offered to you at 6% for five years, meaning you have a monthly payment of $483.32.

You drive this car for seven years. Each month, you pay $483.32 as a car payment. After five years, you own the car, but you’ve paid out $28,999.20 for the loan – $3,999.20 of that being pure interest. You then start saving $483.32 a month for your next purchase – after two years, your savings account totals $11,715.68 ($11,599.68 in savings, plus $16 in interest).

At the seven year mark, you trade in your used car for $6,000 in trade in and also make an $11,700 down payment on your next $25,000 car. You’re still borrowing $7,300 to buy the car, which means monthly payments of $141.13 over the next five years, totaling $8,467.80 – $1,167.80 of that being pure interest.

At this point, you also need to save $285 a month so that you have $25,000 in cash ready for your next car purchase at the fourteen year mark – seven years after this one. $23,940 of the savings will be cash and the rest will be interest – $1,104.64.

So, after all of this, you wind up paying out $73,006.68 over the course of these fourteen years and find yourself with a new car at the end of it.

Now, let’s look at fourteen years starting in a different fashion.

Option 2 – Buying Used Now
You go to the dealership and take out a $5,000 loan to buy a used car that will work for five years. You make monthly payments of $483.33 each month. For the first year, $430.33 of it goes towards the loan payment, while the other $53 goes into savings. For the remaining four years, the whole $483.33 goes into savings.

At the five year mark, you have just shy of $25,000 saved and the trade-in on your junker puts you over the top. New car time, paid for in cash. You then start saving for your next new car in seven years, saving $285 a month.

At the twelve year mark, you replace that car and keep saving the $285 a month. At the fifteen year mark, you have a three year old car and $10,414.67 in savings.

Over the course of all of this, you’ve actually only shelled out $63,199.80 out of your pocket for these cars.

Comparing These Two Scenarios
Here’s the real take-home message here: simply by buying a low-end used car at first in the second scenario and driving it until the owner could pay cash on a new car (at the five year mark), that owner saves $10,000. In other words, choosing to take out a loan for a new $25,000 car means that $10,000 is simply evaporating out of your wallet.

Remember that from here on out, both scenarios are going to be saving the same amount of money in their savings account to keep up with future car replacements, which essentially means that the money is a car payment.

I like to look at it this way: the owner of the second option is essentially paying himself $2,000 a year to drive a used car instead of a brand new one.

There are a few additional things to point out as well.

First, the insurance costs in the second scenario are lower as well. For those first five years, the person owns a used car which will have lower insurance costs than a new automobile.

Second, considering used cars in your buying decision can save you money. When you run the numbers on your car purchase, always include used cars, particularly ones from model years with a good reputation. Sometimes, those cars can save you significant money over the long haul through insurance savings, plus they allow you to retain some of your cash savings for your next car purchase.

Finally, having the money in the bank puts you in control. If you can buy the car in cash, you’re no longer worrying about your credit history or about whether a bank will offer you a good rate. You have your cash, you find the best deal, and you buy. Simple as that.

I’ll say this much: every time I run the long term numbers with regards to paying cash or taking out a loan for a car, I further reinforce my own plan to never again borrow a dime for a car (unless, as I mention above, I have the money in an investment that offers a better guaranteed return than the interest rate of the car loan).

Like a lot of people this week, our family is traveling by car to a number of Thanksgiving dinners. As I taught the children to sing recently, “On the interstate and across the bridge, to Grandma’s house we go!”

Of course, when you’re traveling during the holiday season, you’re opening the door to some potential challenges. Winter weather, overcrowded roads, long road trips, expensive stops – it all adds up to some serious time, some serious cash, and some risk for much more time and cash as well.

With that in mind, I thought I’d share with you some of the preparations we’re doing for this year’s road travels in order to save money and minimize risk.

Air up tires Take the car to the local refueling station. Use a tire pressure gauge to check the pressure in each of your tires (if you don’t have a gauge, ask inside). If there’s inadequate air, use the air pump there to refill each tire up to the recommended maximum found in your manual. If you’re unsure how to do this, most car manuals offer a very useful step-by-step guide for taking care of it.

Perform any scheduled maintenance If I’m going to significantly surpass a scheduled maintenance on the road trip, I get it done before I leave. This usually involves getting a mileage estimate from Google Maps, adding that to my current odometer, and seeing whether or not that new number exceeds when my next maintenance should occur.

Caravan If you possibly can, travel with others in a “caravan” so that, if one individual vehicle has problems, there’s support all around. Driving in a caravan has helped me out more than once – I remember one awful road trip where my son got extremely ill along the way.

Provide an ETA to your destination This way, if you don’t show up on time, they can be aware of your delay and attempt to contact you. Again, this has helped me in the past, as people at my destination were able to realize something was wrong and eventually offer assistance.

Visit the restroom before you leave It’s the Murphy’s Law of road trips: when you think you’ve got everything covered and are making good time, someone has to use the restroom. Remember, as I mentioned above, the more unnecessary stops you make, the more expensive (and longer) your trip becomes, so make sure everyone has used the restroom before you leave.

Pack blankets, sand, hand warmers, and a shovel This is more important for Christmas travel, but I also do it for this trip. I pack blankets to help with situations where we’re in an accident or trapped in a storm – same with the nad warmers. I pack sand and a shovel to help with situations where we might need to get out of a ditch.

Pack hearty meals We pack meals before we leave so that we can eat in the car without having to stop for expensive fast food. We often pack an abundance of food, particularly healthy snacks like unsalted nuts, raisins, and the like, because these serve the dual purpose of sating hungry children while also providing rations in the result of an accident.

Pack a charged “911 phone” (and charge your phone) A “911 phone” is a cell phone without an active contract that is only able to dial 911. Keeping such a phone in the car with you helps in case of a roadside emergency.

Pack a change of warm clothes After a winter trip in which I had to walk almost a mile in sub-zero temperatures without adequate clothing, I’ve started making sure I have at least one change of very warm clothes, preferably coveralls. This is particularly important if you’re traveling in the country on less well-traveled roads.

Make a map and check road conditions This is a tactic that’s more important around Christmas but can still be relevant at Thanksgiving – we’ve been caught in Turkey Day blizzards in the past. Also, before you leave, make sure you know exactly where you’re going and the route to get there.

Travel when the roads aren’t busy We’re traveling during the morning hours for most of our driving, which will avoid most of the traffic outside of towns. If you can, avoid driving on Wednesday evening and Sunday, which are extremely heavy traffic days.

Gas up This isn’t so much a money-saving technique on gas as it is a method to avoid an unnecessary stop at a roadside gas station where, after being cramped in a car, you’re tempted to run inside and, because you’re a bit hungry, you find yourself buying unnecessary stuff. Just avoid the stop entirely and make better time on the road.

Aaron writes in:

I love your cost breakdowns when you calculate the real truth behind some financial choice. I’ve got one for you. Is it really cheaper to ride public transportation to work? I have a bus stop about a block from my house. For about $2 each way, I can use public transportation to get to work, which is about fifteen miles away. But I have a car that gets about 28 miles per gallon and gas is about $3, so I’m breaking even to make the commute and I have a lot more flexibility. I just don’t see how the numbers add up.

In the numbers you give above, you’re neglecting a whole bunch of factors.

First of all, your car costs a lot more than you think. Gas is just the start. You also have maintenance, tires, insurance, license, registration, taxes, depreciation, and finance charges (if you have a car loan). According to AAA’s estimates on driving costs, if you drive a medium sedan 10,000 miles per year, the cost per mile figuring in all of those factors is 70.2 cents per mile.

So, your commute is 30 miles long, round trip. Your cost for that commute in a medium sedan that you drive 10,000 miles in a year (a guess based on the info you provided) is $21.

This, of course, doesn’t include things like parking costs, traffic tickets, and so on.

Of course, if you’re going to own a car anyway, the cost per mile for a medium sedan goes down to $0.39 (according to those AAA statistics, adding together maintenance and depreciation per mile). Your round trip in this case is about $12 in depreciation and fuel costs, with the other $9 coming in as costs related to the fact that you own a car, regardless of how much you drive it.

Another factor to consider is the savings of buying a public transportation pass. I’ll use San Francisco’s BART as an example. If you commute every day for a month (let’s assume 24 days), you’ll spend $2 each way on a commute if you don’t buy a pass, totaling $96. Alternately, you can get a monthly pass costing only $60, saving you $36 a month.

If you commute each day in your car, one that you would own anyway, your depreciation and maintenance costs would be roughly $288 ($12 per day over 24 days). If you only have a car for commuting, the total cost over that month is $504 ($21 per day over 24 days).

The case for saving money on public transportation is pretty clear, in my book. The big argument against it, of course, is speed and convenience, which is what you’re really paying for if you own a car in a large city with good public transportation.

If I lived in a large city, my family would own one car at most (and possibly no cars at all). We would use public transportation as much as possible and, if it worked out, we would simply rent a car for the rare occasions we needed one. If you only actually need a car a couple times a year and can use public transportation the rest of the time, it is far cheaper to go that route.

Remember, that extra cost per month for driving yourself to work is all about the flexibility and a bit of time-saving. How valuable is that to you? A few hundred dollars a month?

Meet our new automobile, a 2004 Honda Pilot, which we purchased as a replacement for our ailing, rusty 1997 Ford F-150 pickup:

We purchased it a few weeks ago, paying cash, while simultaneously selling off our truck. Perhaps most interestingly of all, we found the vehicle on Craigslist, bought it locally, and got a very good deal on pretty much the exact vehicle we wanted.

Why Did We Buy?
Our 1997 Ford F-150 was approaching 200,000 miles and was having quite a few issues, including some significant rusting, engine problems, starter problems, a damaged flywheel, and a few other things going on with it. Not only that, we had a third child on the way, so we knew that we would need at least one vehicle that would comfortably seat all five members of our family, as neither of our vehicles did this really well.

Our primary buying concerns were space and reliability. We wanted a model that had a track record of reliability that also afforded the space for three children at a minimum (and perhaps one or two more).

Deciding What to Buy
We started by looking at Consumer Reports, J.D. Power, and other consumer publications that offered survey-based ratings of both new and old models. We actually began our search in late 2008 (!) by simply collecting data on all vehicles that could seat six or more and were made between 2000 and 2009. This pretty much restricted us to vans and SUVs.

We then began to rate them based on other criteria. How reliable were they according to the survey data? What was the gas mileage like? Does the brand or the model have a history of expensive repairs?

We wound up developing a spreadsheet of various van and SUV models, which I separated into three classes – Strongly Interested, Possibly Interested, and Avoid. The “strongly interested” models (of which the Honda Pilot was one of the top entries) were ones that had a history of reliability and at least passable gas mileage. The “possibly interested” ones had a few question marks but would have been acceptable purchases. The “avoid” models were ones that just weren’t up to snuff.

We then used various pricing sites to come up with prices that we were willing to pay for the models, particularly the ones we were interested in. We did not anticipate much value for the truck – we were largely assuming we would just buy the replacement and find the best way to offload the truck, even if it meant simply throwing a sign in the window and parking it somewhere.

The Search
We then spent fifteen months looking regularly for the right vehicle. We received lots of calls from local dealerships. I test drove quite a few vehicles along the way, as did Sarah. (One lesson learned – I don’t fit well in a Dodge Grand Caravan.)

As time went on, we started to look more and more into “alternative” pathways for buying a car. I discussed the ins and outs of this with a friend of mine with some legal expertise who advised me that I’d largely be fine with direct buys as long as we researched the vehicle ourselves and had a notarized and well-worded bill of sale.

Along the way, we saved diligently for the purchase, putting more than a healthy car payment away each month so that we could pay for the right vehicle completely out of pocket when the time came. We kept this savings entirely separate from everything else and never looked at it as part of our emergency savings.

One weekend, Rachel (click that link to find out more about her) showed us a local Craigslist entry for a 2004 Honda Pilot. The owners seemed to be asking a very reasonable price for the mileage and condition claimed, so my wife elected to give it a look.

My wife inspected the vehicle, test drove it, got the VIN number, and had it inspected. She reported to me that the previous owners were seeking to sell mostly because they needed to improve their monthly cash flow and debt situation – meaning, of course, that they still owed money on the car. She also reported that the vehicle was in stellar condition, as it turned out that the previous owner actually worked on automobiles for a living.

We obtained a vehicle history report for the VIN and didn’t discover any obvious red flags. We met again, where the owner expressed interest in buying my truck at the same time, in effect turning it into something of a vehicle swap with cash added to it. He wanted a vehicle for some very local commuting and, after driving it a bit and poking around under the hood and under the vehicle for a while, said he thought he could patch it up for a year or so and then he would probably sell it for parts.

The Sale
I contacted a lawyer about what steps to take to ensure that this purchase would be successful. He advised us to draw up a very specific bill of sale which indicated the specifics of the sale, that we do the transaction at the bank where the owner’s loan was held, and that we get the bill of sale and a lien release both signed and notarized while there.

So that’s exactly what we did. We conducted the full transaction at the bank, handed over a check, signed the papers, and drove off on our new Pilot. We wound up paying about $1,500 under the blue book value for the vehicle. We received the title within two weeks of the sale and I paid the appropriate taxes and fees at the county offices shortly thereafter.

Are We Happy?
Absolutely. The vehicle has run wonderfully since the purchase and has met our every need. It has plenty of space in the second row of seats for our three children and enough space in the back to haul bicycles (which we’ve already done). We received a full maintenance schedule with the vehicle and figure that we’ll be due for our first significant maintenance in late summer.

In short, we’re thrilled with the purchase. Our patience and diligence paid off – we got the vehicle we wanted for a great price and we were able to just go write a check for it, easy as pie.

Kelly writes in:

For the first time in my life, I have a daily commute to work. I drive about 45 minutes each way to work each day of the week. According to my math, I’m going to be spending about $125 a month just on gas, let alone maintenance, upkeep, and so on. When I look at it that way, my new job isn’t as awesome as I thought it was! What can I do to trim that amount?

Here are ten things I would suggest for anyone who is seeking to optimize their commute and minimize the financial cost of it.

1. Start (or join) a carpool. I wrote an article recently on how to start a carpool, but if you can find one that already exists, join that one instead. It not only reduces the number of days per week that you have to drive, it also allows you to use the more efficient HOV lanes during the commute.

2. Properly inflate your tires each month. Few things damage your gas mileage than poorly inflated tires. Think of a bicycle and how much extra effort you have to exert when your tire is even a little bit flat. The same is true for your car – it might be plenty inflated to make the trip, but if it’s even a bit under the recommended maximum level, your car is working harder to go the same distance, and that eats gas.

3. Find the optimum route. Unless the route to your job is incredibly straightforward, there are several different routes you could potentially take to your job. Spend some time to figure out the optimum route – the one that eats the least amount of gas, in other words. Use Google Maps to help you in this regard. Finding a more efficient route will simply shave transportation costs (and possibly time) off of your daily commute.

4. Identify the low-priced gas stations along your route. Take note of the gas stations available to you along the route and identify the ones that consistently have the best prices (if there is variance – usually, there is). Then, make that station (or stations) your regular stop to fill up your tank.

5. Use a “gas card” for that chain of stations. Once you’ve identified the inexpensive station, sign up for their gas card. Use it just for gas – nothing else – and pay the card off in full each month. The rewards on such cards are often quite nice and can add up to a free tank of gas every few months or so.

6. Examine public transportation options for all or part of your commute. Just because there isn’t a train straight from your home to your place of employment doesn’t mean public transportation isn’t an option. Perhaps you can drive to a nearby station and take a train/bus combination to your place of work. If there is a combination that can strongly reduce (or even eliminate) your commute, you should take it.

7. Use your A/C and heater less. Just use them to get your car to the right temperature then turn them off. You don’t need to leave them running during your entire commute – they just eat fuel. If you find the temperature getting uncomfortable again, just flip the A/C or heat back on.

8. Ask about subsidies at work for commuters. Some places of employment offer benefits for commuters, such as reimbursement for miles driven. Don’t be afraid to ask your human resources contact about it, just to see if it’s available. If it is, it’s cash in hand for you.

9. Leave a bit early to avoid the rush and to avoid the need to speed. In the morning, get in the swing of leaving a little bit earlier. This way, you can avoid speeding (which conserves gas and also helps to ensure you don’t get a ticket) and also potentially avoid the worst part of the rush hour traffic.

10. Look into telecommuting. If your job allows it (and the workplace allows it), consider telecommuting a day or two a week. Those are days where you’re not commuting at all, which means a nice net savings for you.

Beyond these tips (which are things you can do right now), I would suggest car shopping with fuel efficiency in mind when you go car shopping the next time. It’s okay to pay more for a more fuel-efficient car. For example, let’s say your commute is 40 miles each way, which totals up to 2,000 miles a month. Assuming gas is $3 a gallon, if you get a car that gets 20 miles to the gallon, you’ll be spending $300 a month on gas. On the other hand, if you buy a car that gets 40 miles to the gallon, you’ll only be spending $150 a month on gas. That’s a $150 savings each month, more than enough to make up for even a sizeable difference in car payments.

Good luck with your new job!

Jenny writes in:

I work at an office park about forty five minutes from where I live. I live in a highly populated suburban neighborhood.

In order to save some money on gas and wear and tear on my car, I want to start a carpool, but I don’t know anyone who lives near me who works in the office park. I don’t mind stretching my hours a bit to make this work, as I could go in with them a bit earlier and do some busywork (email and the like) to start the day or read a book at the end of the day.

The only problem is I don’t know how to get this kind of thing started and I don’t have any obvious people to ride with. Any ideas?

Carpools are a tremendous way to save money. My wife is in a (semi-functional) carpool with a coworker and often has a ride to work two days a week. We estimate that it saves us at least $100 a month in gas and maintenance costs. It would be truly great if she could get another person or two into the carpool.

How can Jenny get a carpool started in her situation? Here’s the game plan I would use.

First, I would make up a very clear flyer that stated my first name, my cell phone number, and the fact that I wanted to start a carpool from the neighborhood or city where I lived to that office park. I’d probably make some “tear-off” tabs on the right hand side of the flyer so that people could yank the number off and put it in their pocket. Put “car pool” above the number.

I would then take a copy of this flyer to each office in the office park. There may be a lot of offices there, so you may need quite a few copies. Ask for permission to hang the flyer on the office bulletin board in each of those offices. Given your situation, I would imagine most would let you do this.

Ideally, you’ll get a few calls within the next few days. You’ll need to get some key information from each person, so you may want to carry a notepad with you.

From each caller, get the following:
+ their name
+ their cell phone number
+ their address (so you can map their location)
+ their approximate work schedule (so you know when they would need to depart/arrive)
+ any “special” days they have (like my wife’s carpool, where it doesn’t happen on Fridays due to a special need of her carpool mate)
+ what types of vehicles they have and how many it can seat

Once you have this information from a few callers (give it a few days), set up a schedule. Figure out a departure time (both from your town and from the office park) that works for everyone (or at least for the largest number of participants). Also, figure out a rotating driving schedule.

Once you have this information, call each person in the pool back and let them know when the pool will begin. I highly recommend you drive the first day.

When you do the first day, pick up the other people on the route and give each person a list of addresses, phone numbers, and schedules for everyone in the pool. I recommend that you make the schedule as simple as possible, even if it inconveniences you. The best way to do this is to say that Person X drives on Mondays, Person Y drives on Tuesdays, Person Z drives on Wednesdays, and Person A drives on Thursdays, with Fridays handled on a rotating basis. If you have five people, this is really easy. If you have three people, have Thursday and Friday rotate. If you just have two people, have each person drive two days and have Friday rotate.

Yes, this is a lot of set-up work. But you’re the one who has the initiative to start the carpool and you will save a lot of money on it. It may take a bit of extra effort in setting it up and an occasional headache when someone is sick, but it will be worth it in the large savings you get, especially with a four or five person carpool.

Good luck!

This is part of an ongoing series about how to trim the budget of the average American. As this series focuses on such broad-based tips, some will work for you and some will not. You’re invited to mention in the comments the tips that you found to be the most useful for inclusion in a comprehensive budget trimming guide at the conclusion of this series.

Transportation – gasoline, motor oil – $2,384

The average American family drops $200 a month on gasoline and motor oil – and that’s at early 2009 prices for gas, which were significantly lower than prices today.

However, this is one of the easiest numbers to trim in your entire budget. There are several simple steps anyone can take to reduce their gasoline usage without making radical lifestyle changes. Here are twelve options.

Form a carpool (or join an existing one). Even if this is an irregular carpool – my wife, for example, carpools with a friend two days a week, saving her one day of driving – it still saves you signifcant fuel costs on your commute and wear and tear on your car. In some localities, you also gain the option to use HOV lanes, which can add to the fuel efficiency of the drive.

Use public transportation. If you have easy access to public transportation, it is almost always a fuel saver, particularly if you can use such transportation routinely. Even if you can just occasionally use the bus system or the subway, it still leaves gas in your tank.

Use a bicycle – or your feet. Alternately, use a bicycle – or your own feet – to reach nearby locations. I often walk to the post office instead of driving there – it takes substantially longer, but if I use a brisk walk, I can get a moderate workout from the situation, making me healthier, while also saving money on the fuel.

Buy a more fuel-efficient vehicle. If gasoline is $3 a gallon, moving from a 20 mile per gallon car to a 25 mile per gallon car saves you $360 a year (assuming you drive 12,000 miles a year). If you’re buying used, such a savings can make it well worth your while to invest a bit more in a more fuel-efficient car.

Change your own oil. Not only will you save on the maintenance costs if you’re not paying someone to do it, but it also gives you much more control over the actual oil that goes into you car – and much more power when it comes to comparison shopping for that oil. Study up on the type of oil that’s truly best for your car, then shop around for it. You’ll find a great price on the best thing for your vehicle – a win all around.

Drive the speed limit, especially on the interstate. Stick in the slow lane and stick with the speed limit and you’ll find yourself saving quite a lot on gas. “But everyone’s going 90!” If that’s the case, and you still choose to drive there, then you’re paying a substantial amount to drive at that pace.

Keep your windows closed – or your air conditioning off. If you’re driving in town at low speeds, keep the windows down and your air conditioning off. However, if you’re out on the open road, do just the opposite. The wind drag when you go at higher speeds becomes significant, exceeding the fuel costs of running an air conditioner. Alternating between the two will save you the most money.

Minimize the “stop and go” when you’re driving in town. Instead of gunning it out of a stoplight then just slowing down again to a complete stop at the next stoplight, accelerate more slowly out of a stoplight and slow down gradually well before the next one. You’ll maintain much more momentum (and thus retain fuel) by slowing gradually rather than slowing quickly, stopping, and then accelerating from a stop.

Re-evaluate your routes. Are you taking the most efficient route to your regular destinations? Many people lock themselves into the first route to their destination that they discover, not bothering to investigate further and discover shorter routes. Doing so saves on fuel costs, wear and tear, and your valuable time.

Keep your tires properly inflated. Ever tried a bicycle with partially deflated tires? It’s hard work to pedal. Improperly inflated tires on your car cause your car to burn a lot more gas to get going. Given that it’s really easy to properly inflate your tires at your local gas station, you should take advantage of the free air to save yourself some cash.

Remove excess weight. If you’re carrying items in your car without a good purpose, remove them – they’re just slowly milking your fuel efficiency. Go through your trunk, your back seat, and the bed of your truck and look for items that don’t need to be there. (The same goes for fuel itself – you’re better off refueling when you’re close to empty than when your tank is mostly full – though the effect is tiny.)

When you’re stopped, turn off the engine. Whenever you’re going to be idling for more than fifteen seconds or so, turn off the engine on your vehicle. Idling just causes your car to burn gasoline without providing any forward motion for you – and even just a few seconds’ worth of idling eats more gas than is eaten during ignition.

I want your help! In the comments, please let me know which of the tips you find most useful for trimming these costs. I’ll include the top choices in a comprehensive budget trimming guide at the conclusion of the series.