Refill kits
I've had mixed luck - good luck with black, bad luck with color. The color refill turned out to be very messy and it was very difficult to get one of the chambers full (the yellow died in only a couple of weeks). The black cartridges that I've filled worked pretty well. The only downside I saw was that it "dried up" much quicker (lasted ~half as long) than a new cartridge. But the economics still work out in your favor.
Okay, the above was a long-winded way of saying that I recommend refilling black. The color cartridges may be different. They weren't worth the hassle for me. YMMV.
