You can set up a wireless network to print on one printer with both computers without running cables. The software for the network card should know what computers are addressing it (I haven't done this, so won't try to get more specific except to say it can be done).
I'm going to have to buy a new cartridge this month for my laser printer. It is large capacity, and there are two sizes. One is $60, the other is $120. Like Rapaire says, these are a lot less than the cumulative colored ink cartridges. The big laser cartridge will probably last for a couple of years. The smaller one that came with my HP 1320 lasted about 10 months.