Not possible unless you get all used parts, and that is not advisable unless you have experience at it, as you have to know whom you can trust as far as what condition they're in.
If you already have a display you can use, a PS4 or Xone is a good alternative in that price range ($300). If you suck at using gamepads like me, the XIM Apex is a pretty good KB/M adapter, but it costs $100.