Many of us (myself included) have an ink jet printer at home for home printing needs. We certainly use ours for lots of things, from printing off forms to making pictures of our children for various uses.
It's also widely known that it's possible for people to refill their ink cartridges. It's fairly simple to do, except that different cartridges have different procedures. Here's an example of such a procedure for an HP 970CXI printer:
You can find the correct procedure for your particular printer's cartridges by searching on YouTube and/or Google.
Here's the real question, though: does this practice actually save money?
I did research on the prices using my own printer, a Canon Pixma MP480. You can purchase a refill kit for this printer type for $24.99 plus $6 shipping, a consistent price I've seen from many vendors. This refill kit will refill the cartridges you have approximately six times. The best price I've found for cartridges for this printer is $59.88 for a double-sized color cartridge and a double-sized black and white cartridge - two color refills and four black and white refills. Refilling it yourself saves you about $7.50 per cartridge refill, in other words.
There are drawbacks to this plan, though.
First, it can be very messy. When I attempted to refill a cartridge, I got ink on my hands that was very hard to wash off and stayed on my skin for a week or so. This, of course, can be avoided by wearing gloves to protect your skin - something I strongly recommend.
Similarly, there's a risk of staining your clothes and your work area. You're going to want to do your refilling in an area that wouldn't be disastrous if ink spilled all over. I recommend spreading some old rags out and doing it in a garage or on an old table. Similarly, wear your old junky clothes when doing this - jeans with stains on them or old t-shirts are perfect.
Second, the ink is often not as good as normal ink. If you're just printing off pages for personal reading or forms, you're probably fine. However, if you're printing off photographs or items you want to put on display, the color difference is often noticeable. One solution to this is to switch out your cartridges depending on your printing use, but that can turn into a real hassle over time.
One good way to avoid this is to shop around for an ink refill kit with a guarantee on it. You might end up paying a premium for such a kit, but that's acceptable.
From my own experience, the ink refill kit I used with my own printer cartridges was not worth the savings to me. The cartridge refill did not seem to last long and even after a small number of pages, I was already noticing fading. Since we usually print our own photographs, this was unacceptable to us. According to my back-of-the-envelope math, the cost per quality printed page was very high with the refilled cartridges, higher even than buying new ones.
After this experience, I discussed ink refill kits with several people who I know in the IT field who use printer cartridges in the workplace. Most of them have similar comments - they work fine for internal use where crispness and the deepness of the blacks isn't a big deal, but for external use, they would either use a new cartridge or a refurbished cartridge with a warranty. Refurbished cartridges generally aren't available for low-end home ink jet printers; that option mostly applies to larger printers.
My conclusion is simple: ink refill kits work if you're not printing photographs or other documents that you intend to share or archive. If you mostly just print off recipes and such, ink refill kits will easily meet your needs and save you money. If you're printing off mostly photographs and high-resolution documents where color and crispness are important, shopping around for the best deal on new cartridges is probably the best use of your time, money, and energy.
In other words, it all comes down to how you use your printer.