Dirt cheap PCs

[Grauniad]

Newegg from time to time runs combo offers on components. They are probably very good for budget, low-end gaming (entirely suitable for CW3).

Here's today's $180 deal.  Note that you'll have to fork over some money for the Windows (currently $100 for Windows 7 Windows 8.1, although from time to time I see $80 offers in my email). You should also keep a small amount of money handy for a graphics card if the built-in graphics in the AMD APU is not sufficient. A decent, low-end card may cost $60-80. Recon on <$400 all-in, but as little as $280 if you plan to install the GPU later.

Edit: Removed the link since it linked to the current Shellshockers, not to the product specifics of the old, now unavailable deal.

[Clean0nion]

Got my laptop for £250 at Cash Converters (a chain pawnshop if you havent heard of it). 6GB of RAM, 2.2GHz processor, that's all the information I know, note my lack of knowledge. It's worked perfectly for me thus far (although the most CPU I ever use is when I have CW3, Skype, TFM and Minecraft open at the same time).
I'd call that, by your standards, dirt cheap.