Today only. Newegg has the COOLMAX ZX Series ZX-500 500W ATX12V v2.2 / EPS12V v2.91 SLI Ready CrossFire Ready 80 PLUS Certified Active PFC Power Supply for $30 - $10 rebate
[Exp 9/30] = $20
with free shipping. Features a single +12V rail at up to 34A, and a 140mm silent cooling fan.