Well it'd be nice to stay at around $100, but I could go higher. I've always skimped out on power supplies. Maybe I should get a nice one now..
I'm going straight in with an over-budget option, $140 after rebate gets you this Seasonic X 850w which is one of the very best on the market
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151102
Modular, very quiet, very high quality, 80 Plus gold and it can pull over 1000 watts when stressed, you'll really not go wrong if you can afford it.
Fake edit - You can get this 750w XFX Gold PSU which is just the Seasonic I posted above rebranded, would be my choice and it's a bit closer to your budget too at $120
http://www.newegg.com/Product/Product.aspx?Item=N82E16817207029
Basically flawless according to this review http://www.hardwaresecrets.com/arti...ition-Full-Modular-Power-Supply-Review/1695/1 and can pull 950w under full load. Would definitely be my choice.