OK, here's a terrific power supply deal for you.
1) Create a Newegg account and sign up for the email newsletter. You will then be able to use the coupon code on the product page.
2) In addition, if you're a new customer (or you're using a new email address to create a new account) you can also use the coupon code "NEWCUSTOMER10" for an additional $10 off. USE THIS CODE FIRST IF YOU QUALIFY.
3) After the mail-in rebate, you'll get this PSU for $20 + postage for the rebate.
Is it a good PSU? Well, it's built by Seasonic (an excellent PSU manufacturer), has 48 amps on the +12v rail (which means it will power an overclocked CPU and ANY video card up to a GTX 580) and it's compact enough to fit in just about any case. It is also very quiet. As a matter of fact, its only drawback is that it doesn't come with a power cord. It's more than what you need, but it's a very cheap, high-quality unit that you'll be able to use later on in a new computer; whatever its power requirements may be.
I'll just put it to you this way: it's been powering my main rig (Core i7 930 @4.1GHz/6GB RAM/GTX 460 @875/1750/1990) for over a year and a half now without a hiccup, and I trust it implicitly. It's a freaking tank.