Finding a nice Prom dress

I have been looking around for a cheap prom dress and it is turning out to be very difficult. I am having trouble because I have a very curvy figure and therefore can find that some dress designs just make me look very round. I want something which will really flatter my figure and because that sort of cut is not in fashion at the moment, it is proving to be hard to find something. Obviously it needs to be an affordable prom dress as well and for me that is also not that easy, because many dresses are extremely expensive. I am trying to look for sales but I find that they only seem to have very small or very big dresses and nothing in my size. It is getting to be very irritating and I am beginning to wish that I could afford to pay someone to make one. I suppose I could have a go myself but patterns and fabric shops are so rare these days that I would not even know where to go to enquire as to where my nearest one was. I know that all of my well off class mates will look stunning and I just hope that I can too.