Is this what you're looking for?
http://www.amazon.com/SHOP-FOX-M1011.../dp/B001R23S7W
(that one is kind of small, but it fits in your budget and I'm not sure exactly what size you are looking for). For under $500, you're probably not going to be able to get a decent width (24") and you probably won't be able to bend up to .125" (I assume you're looking to bend aluminum, but I'm not sure).
My old team bought this one (
http://www.amazon.com/M1042-24-Inch-...d_sim_sbs_hi_1) last year, but it's a little bit out of your budget (definitely worth the extra money though), it's worked very well so far.