You don't need $800+ to have a good gaming rig, really. If you're fine playing games on high/medium settings a $500 computer can run everything besides the occasional glorified tech demo (I'm looking at you, Crysis 3).
Note: I define a "Good" rig as something that can run the currently 'high end' games at the time with medium settings at 40+ fps. Running (literally) everything on max settings 1080 60fps is not a good rig, its a behemoth monster machine.