The cheapest and easiest way would be to go get a cross over cable. YOu wouldn't even have to get a big one because your computers are probably pretty close. Probabloy would only cost like $3 plug each end into each machine. Check each computers work group, you can do that by opening the properties for "My Computer" Make them the same, and then map a new network drive from the tools menu in "My Computer"
Hope that helps a little