Pretty much as cheap as I can keep it. Can I do it for under 80? I can squeeze over 100 if need be.
I don't think my temps are getting that high, so it's gotta be this shitty budget 500 watt psu.
The EVGA B 600 watt power supply for $35 after $20 rebate is the cheapest I can recommend, it's an average power supply, not too high quality but it gets the job done. Otherwise for something a bit stronger and proven good quality, the EVGA Supernova B2 750 watt for $59 after $20 rebate is pretty good, rated very highly by Jonny Guru.
It's a pretty big jump from $35 to $60, but currently there's not much to recommend in between. The only quality power supplies I see that are worth recommending are either a bit too low in wattage (Rosewill Capstone 550 watts for $50 after $20 rebate) or cost so much you might as well pay a few extra dollars for the EVGA model (XFX TS 650 watts for $55 after $20 rebate).