If you want to go cheap and get a wireless router without a USB port, it's quite convenient to just plug the printer into one of the computers and turn on printer sharing. You have to have that computer on to print, but if it's on anyways, it works out just as well.
Also, the iMac adapter card
is much cheaper than that. It was only $20 when I got mine 2 years ago. They must have been discontinued or something.
