Hey again ... im sorry but $15 is just not going to cut it to run a power-sucking card like a 480. Good sales appear sometimes that might get you down into the $40 range, but thats the bottom for PSU that you should be using. Its not worth possibly destroying your entire computer
in order to save a little money.
This is as low as I would go at the moment:
CORSAIR Builder Series CX500 V2 500W ATX12V v2.3 80 PLUS Certified Active PFC Power Supply -- $39.99 after $20.00 rebate(s)http://www.newegg.com/Product/Product.aspx?Item=N82E16817139027
I'll post back if I see any really good sales.