There are plenty of printers to choose from colour and black and white. I have a StyleWriter 2500 and the BC21e cartdrige doens't last long (it has a tendancy to print lines). If you buy a StyleWriter and insert a Black only cartridge, they last for a while and they are refillable.
You could get a good Epson printer like the 850 (I think) that prints good quality colour and has Serial and USB ports (if you upgrade to a newer mac). If you have the money you could buy a Laser Printer with an ethernet card and connect that to you mac.
Things to avoid are very old printers (etc HP DeskWriter, ImageWriter) because they usually had a long life and their mechanical functions don't work to well (Our school has a heap of HP DeskWriters which don't work).
Any Semi old printer will do that has a serial port since all you want to do is buy a printer that can print black and white. Buy one that is cheap to run and that has ink cartridges that are refillable. It's hard to point you to the correct printer because there are no new Serial port printers and a very large range of semi-old printers.
Another option is to buy any OHCI compliant PCI USB card and insert that into your computer but if the Ethernet card takes up that PCI slot, you would have to take it out (Unless it occupies the Comm. Slot)
Most people will tell you to get an epson.
). He was quite happy with his print outs, for the most part.