What you can do is go to a store like Office Maxx and check out the prices of ink and see which brand seems to be cheaper than the rest. Mt wife is big on not spending a lot on certian things and ink is one so we have a HP Printer. It has black and then three seperate color cartridges. If one of the colors runs out you can just replace the one cartridge. The ones with the tri-color cartridge can be wastefull because your not going to run out of all the colors at the same time.
Plus you can get the XL cartridges and that saves some money because you get a larger cartridge and it's not double the cost.