I got my cool master for 25$ which is cheap(was on sale), it has 450 watts and dual 12 volts. Id say thats cheap and good Just watch around for rebates and deals. Thats how i try to by my stuff. The psu i got is normally 75 (Had 25 dollar instat rebate then the 25 mail in rebate.)
On the subject of PSU's... let me say this (from personal experience). You get what you pay for... DO NOT, I repeat, DO NOT cheap out for a PSU. Pay more if you have to for a quality PSU as oppposed to saving a few bucks on a cheapo model...
I couldn't agree more here, don't want to risk ruining the other components of your computer with a cheapo PSU, spend the extra $$$!
if looking for quality psu try Antec, Enermax or OCZ.. recently i thought of buying this.. http://www.enermaxusa.com/catalog/product_info.php?cPath=21_45&products_id=83
