DO NOT I REPEAT DO NOT Get a cheap PSU.
I was once at a friends house after about 2 weeks of getting his new rig. All fancy components, nice new i7, gtx 560 ti, 8gb ram, the lot.. guess what happened. Playing some world of warcraft for about 3 hours. Next thing you know, BANG, yeah the processor and gpu got tooken with it and would no longer work. I seriously don't recommend getting any cheap psu without 80+ at the risk of losing the rest of your components