Just a thought.
I have available a number of second-hand server boxes. These machines have recently been de-commissioned (from their previous life in a call-centre), but it occurs to me that they would make for a very robust and cheap PC (with very little effort and cost) if anyone was interested. They could equally be commissioned as a server of some sort for either home or office.
The machines themselves are HP Proliant ML350 G3 or ML370 G3. (specifications and descriptions at these links)
Outline Spec As They Are At The Moment:-
1 x 2.80Ghz Intel Xeon Processor Dual Core - Memory: 0.5 GB - HP Smart Array 641 or 532.

So, what would you need to make a functioning machine Hard Disk/s. Monitor, Keyboard, Mouse, Operating System. The Proliant is a very robust workhorse of a machine, which will run pretty much any operating system that you choose to chuck at it. They machines have been around in various guises for a good many years, and so spares are plentiful and cheap, and the user/administration knowledge-base available is vast.
I would be looking for 30:00 per machine as they stand, and I estimate that a functioning PC could be put together for around 100 or so (even cheaper if you have an old monitor kicking about). Freight/Postage would need to be considered as these boxes weigh in at about 20Kgs a piece, (I am based in Hampshire).
Please drop me an IM if you want to ask any questions or to discuss the many options.