Where can i find a dress for homecoming?

I know that there are semi-formal dresses everywhere. BUT, all the stores I could go to are stores that every girl at the school would think to look at. Umm so does anyone know of a good, reliable website where I can get a dress that isn't super expensive? Under 80 dollars if that helps. And the dresses can't be super short and skimpy. I want something that actually has fabric to it! Thanks a lot for any answers!