Speedy Metals on Ebay is a great store to buy from. That's where I buy my 1/8" x 6" x 48" (which I need more of), 1/4" x 2" x 48", and 1/4" x 3" x 48". The surface of their aluminum isn't of the highest quality by any means, but for the price and for what you are likely to be using it for the quality of the surface should be good enough.
EDIT: All of the stuff I get is 6061-T6.
SH Z-Car, Custom Crawler, 8s Savage, 12s XTM XLB 1/7 buggy, 4wd 4-link rear/IFS Pro4 truck, Custom Hyper 10 Short Course, Belt-Drive Mammoth ST 1/8 truggy, 4s 17.5 MM Pro HPI Blitz
Travis, I want to try out 7075, for the price, and its cut to what I want, I just have to do the little stuff. Im going to try online metals. I will order today