well you could find all the best parts that each has and put them all together into a decent comp. Take the biggest HDDs, the most RAM, the one with the fastest CPU...ect. Do you have any specs on them to see how old they are? and whats the use in the $3 price tag?
You could make a folding farm out of them (folding @ home). If they are fast enough- makes game servers. Make keychains out of some of the parts (ram, gpu, ect) and sell them. Or have a bunch of large door stops.
buy them....they might be good for litle upgrade,
You might also be able to get some stuff in them and put it in to your PC,
or, like previously said, take the best of all of them, and make a good one.
That would be greaqt getting all of those PC!
Take the best parts, make a decent pc or two. If they're old: backup boxes.
Don't need 'em all? Donate to a worthy charity, school or needy family with kids.
Like kobaj said: Folding@Home farm.
Any parts left over? Try to test the parts if you can, then sell 'em.
Tom
Man you're lucky! If i can get my hands on 3 bucks computers I would finally be able to complete my suitcase computer. Get the computers, you can think of what to do with them later.