Have you checked local dress shops. I was looking for something nice and formal for a party and stopped by a local, independent dress shop not expecting to find much in my price range a found a lovely beaded dress for $150 then asked about a discount and she gave me an additional $20 off. Watch out for beaded gowns though, they are heavy.
I about chocked when my sons girlfriend got her dress for $650. Is that just goofy or what?