Cheap Reliable Power Supply?

I need a cheap psu(power supply unit) that will support my Radeon HD 4850 (about 470w required I think... maybe 500w to be safe) but I want it to be reliable aswell. All the reccomended psu's are expensive, most more so than the graphic card itself. So I need a cheap and reliable psu to supply my Radeon HD 4850. Does anybody have any suggestions?

Radeon HD 4850 requirements: 450 Watt or greater power supply with 75 Watt 6-pin PCI Express® power connector recommended.

Thank you!

(preferably under 50 dollars please)

http://www.tigerdirect.com/applications/category/category_slc.asp?Sort=4&Nav=|c:1079|&Recs=30

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2010090058%20113143478&bop=And&Order=PRICE&PageSize=20

If you have a Microcenter near you I just got my Antec 500watt not too long ago for 49.99$, its a brand PSU and it has decent power across the board.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817159066

this one i used once in a build for a buddy wit a 9800gt in it which uses about the same amount of power.. odds are this one would do.