Problem 1. The reduction in cost on any of these three bags is a flat $5.00, so no matter what you are saving $5.00 at a minimum. The simplest way to find the cheapest product is to find the unit cost relative to the *largest* unit, so the biggest bag. How many little bags make a big bag? Five. Ok, so we know the little bag is $8.00 or $40.00 for “one big bag worth out of 5 little bags”. The medium bag is $15.00 per or $37.50, and would be “one big bag worth out of 2.5 medium bags. And finally the big bag is $27.00. Subtract five dollars from each of these values as a function of the biggest bag to get your net cost, $35.00 (4 lb bags), $32.50(8#), or $22.00(20#).

It is great to use unit costs, but sometimes its best to think about the units relative to what you normally buy rather than an arbitary amount of pounds. The reason for this is illustrated below:

If I need a 20 pound supply of cat food for my cat, should I save a bit by buying 20 pounds up front in bulk or is my money more useful elsewhere? Twenty pounds up-front costs me $22.00 with my coupon, but I could go with the cheapest amount as a hold-over, and I found out that would cost me only $3.00 with the coupon. That means I have $19.00 left over until my four pounds of cat food runs out. Now, if you can take 19 dollars and utilize it how much do you have to make on that 19 dollars to break even (before you run out of cat food) on buying the 4 lb bag of cat food?

The answer is pretty simple, and you find it by comparing the other way: how much would four pounds of the twenty-pound cat food cost? The answer is 27/5=$5.40. Now just subtract $5.40 from the standard cost for just 4 lbs of $8. You are losing $2.60 every time you purchase 4 lbs instead of 20 lbs, but you are gaining the opportunity to have 19 dollars available to you for the amount of time that 4 lbs lasts (This follows exactly the same financial mechanics as a loan, but backwards).

The simplest way to put this for cat food and most supplies is that the bigger you buy, the cheaper it gets. The savings will hold no matter what the coupon is for. If you don’t have a good emergency fund in place, you might have to buy the 4 lbs of cat food to pay your phone bill some month.

But know that it costs you $2.60 *per 4 lb bag you buy* regardless of your coupon savings, no matter what.

I buy Juicy Juice (with the veggies since I won’t eat them) with a $1.50/bottle off on-line coupon, the clerk then gives me a $2/bottle off coupon for V-8 Splash. While the name brand is usually more expensive, it isn’t usually $2 different. I will have to keep an eye on the quantity now though.

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For example, I don’t buy packaged pasta salad or flavored rice, although I like them, because I can make them cheaper from scratch.

Sometimes, however, there is a coupon that makes one of those items free, or less than 10 cents or so. I can’t make it cheaper than that.

So, “would you buy it without the coupon” is really a very complicated question.

I don’t think anyone raises a cat to save money.

More cost effective to eliminate the weakest links in the food chain.

We have two cats and stick to the 8 lb. bags because we worry that anything larger will be 1. hard to store, and 2. go stale before they eat it all. (Our cats also get wet food, so they don’t eat as much dry food.)

What I do is use the excellent coupon on the smallest bag and then go back to buying my usual (cheaper) brand the next time. I mix the two together as to not hurt the kitty’s systems.

I also disagree with the “would you buy it anyway?” because you can easily get FREE items with coupons that you might not ordinarily buy. For example the latest WalHell magazine “All You” has a coupon for free Adidas Deodorant. While I wouldn’t choose that brand, if it’s free I will! :) I will either use it or give it to one of my kids to use.

Part of saving money with coupons is being VERY flexible on brands. IMHO

Most of my shopping is done on the way home from work, I’m driving within 1/4 mile or less of several major store chains just in my neighborhood anyway, so a small diversion to stock up has almost no travel cost as I’m on the road anyway.

Saving 5 dollars but losing 1.60 is not great, but it’s not the worst thing in the world either.

The key point here is that it’s an ITEM you would normally buy, just not the brand. If a pair of shoes is a “really good deal” but you don’t need them, it’s a bad move to buy them. If an off brand of your favorite cereal (or diaper) is on sale, then buying it INSTEAD of your normal brand would be a very reasonable decision.

Re: The post in general.

I completely agree with the sentiment here. I’ve always been bothered with the posts that talk about coupons, because of the focus on maximizing your dollar on that particular trip. This is a much more practical way to look at things. In addition to the money spent, buying smaller packages can result in more frequent trips to the store (which cost extra in time/gas/etc).

If you buy the smaller bag with that coupon, for the best unit price, you have to add up what it cost you to get the 20lb bag amount.

You got a good deal on the 4lb bag, but buying 4 more of those at the regular price to get 20lbs that you could have originally used the coupon for wouldn’t be that good of a deal.