Here is a nice Thermaltake TR2 500W
ATX 12V Computer Power Supply W0379RU, Supports SATA and PCI-E for $50
But this is a better one but you got to mail in a $15 rebate but hey it's a good one. It's the Black OCZ Fatal1ty
Series 550W ATX12V v2.2/EPS12V Modular Computer Power Supply, Active PFC, SLI Ready, 80 Plus Certified, w/ 135mm Fan, Model: OCZ550FTY. I think you'll be happy with either of these.