I haven't used these guys yet, but found this for a good deal on remanufactured inkjet cartridges:
Pacific Ink
Definitely read their fine print, since they'll only offer a 180 day guarantee on their refilled cartridges, but their prices seem pretty good for someone like me, that's just doing the day to day printing at home.
Reseller Ratings doesn't show any feedback for them, but I checked BizRate, and they're showing a great rating!!
BizRate
I also found this place on Yahoo, that had about the best price I found for remanufactured Lexmark cartridges:
Triangle Cables
No listing on either reseller ratings or bizrate, but it's a yahoo shop......so if they screw you, you should be able to get Yahoo to shut 'em down!! LOL