Newegg.com has the Antec TP-550 ATX12V & EPS12V Power Supply for a good price.

Pricegrabber Price : $89.99 ~ $119.95 Shipped

1. Newegg Price : $89.99 Shipped
2. Use coupon code EMCYTZT277 to get $25 off
3. Rebate Price : -$25.00 ( Exp : 02/01/11 )
Final Price : $39.99 Shipped After Rebate