I don't know if this is a possibility... but...
I've seen older computers on ebay, that are inexpensive.
I've also seen on Tiger Direct, some systems without an OS, that are very reasonable.
http://www.tigerdirect.com/applicati...5897&CatId=119
It probably isn't the answer you're looking for... but if I had to do this, I'd end up buying an off-lease computer and using it as a serverl