Cheap Windows 8 Tablet

The pro version, which also runs normal programs, not just the m$ store type apps, will only run on hardware that uses an x86 type of CPU. It won't run on or install to ARM type processors which the cheap tablets use (and also most  android tablets). For those you'd need the windows 8 RT version, and that isn't available as software to the public, it rather comes pre-installed from the manufacturers (and a further m$ requirement for those types of tablets is that secure-boot must be enabled and can't be disabled, which means you can't install any other OS to those tablets). Apart from that the RT version of windows 8 can only run the store-type apps (plus m$ office), so you are extremely limited with it.

If you get a tablet for Windows 8, you'll also have to get one that meets the minimum resolution of 1024x768, it doesn't support lower resolutions. I don't think there is any intel/amd based tablet available currently that supports windows 8 for the price you are asking.