well, if you're looking to print colour posters, you'll have to get a colour laser printer, which are usually very expensive. then again, if you get an inkjet printer, you spend a good deal of money on ink cartridges anyway, though it's still cheaper than buying a colour laser printer. i personally would recommend going to a copy center and getting them to make it. it's more professional, less of a hassle, and probably cheaper.

edit: outposted!