We've been saying this for years and believe me, it's caused some of my greener friends to look at me like a three-headed pumpkin, but I stand by it. If you have a simple, no frills ink jet printer and you need an ink cartridge you're looking at $20-$40 for color and black. That's between $40 and $80 for ink alone. Now, check Best Buy, CompUSA, Wal-Mart, etc and I bet you can find a brand new printer in that same price range. Keep the old one handy for a donation, backup, etc.
I know, a bunch of you savvy shoppers are scoffing at buying manufacturer brand cartridges for the prices I mentioned, and I agree. Sometimes however th particular model you have doesn't have a generic available, or Wal-Greens wont fill it. You can fill it yourself with a kit but trust me, ruin one counter top, bathroom rug, shirt and family cat and your significant other and/or parents will put a stop to that practice. Besides, sometimes you just need it NOW! Wal-Mart almost always has cheap printers...now.
Thanks to Consumerist for having the fortitude to come forward with this wisdom.
PS - Last bit of advise, make sure the printer you are buying has real cartridges. Sometimes manufacturers (they are all guilty of this sometimes) will put in a 'demo' set of cartridges that might only be good for 20 pages or less.