Ghwellsjr's advice is right on target. the IP3000 has only three dye-based cartridges (used for color printing of photos and graphics), yellow, cyan, and magenta, and a large black pigment-based cartridge that is used on plain paper for text printing. The IP4000 printer has FOUR dye-based cartridges, including black, and the large black pigment based cartridge for text. The IP4000 printer does remarkably good photo printing for a four dye-based cartridge unit, but I really don't see many of them on Criags list. You should stay with at least one of the five cart printers like the ip4000 unless you want to move up to a six or eight cart printer that is primarily for photos.
To stay with the BCI-6 cartridge you might see an ip5000 for sale occasionally. Very good for photos. I also see the occasional i960, an excellent photo printer, but it has two additional color dye-based cartridges, lighter colored cyan and magenta.
The next generation of Canon printers use cli-8 cartridges. They have a computer chip on them that must be reset after being empty and refilled. This is not a big problem as there are inexpensive resetters available. I found an ip4300 printer for $25 that was almost never used, and I gave it to my granddaughter. I also found an almost brand new ip4500 printer on craigs list that I have on a shelf as a spare when my current printers die. the ip4500 is reputed to be one of the best Canon printers of its generation of carts (cli-8) in the five cart catagory. For serious color printing in wide format there is occasionally a very good deal at craigs list on the Pixma Pro 9000 mk II. These printers were offered with the purchase of some high end Canon cameras, and they are being sold on Craigs list. The asking price varies from $135 to $250, but it is sometimes available at $100 brand new in a factory sealed box. This, however, is a BIG unit in terms of desk space and a BIG jump from an ip3000! It is an 8 cart printer.
The short story - try to find a five cart bci-6 printer as suggested by ghwellsjr. If you can't find one that works properly you might consider a later generation unit that uses the cli-8 cart like the ip4300 or preferably an ip4500.