The theme is night out, but I don't have a lot of money and I know bodycon dresses are cheap!
Most Helpful Girl
You can if your school allows it in the dress code, I don't see a problem.
If your budget for a dress is $100, believe it or not my dress in this pic was actually $100 dollars so, it is possible to find a gown for that price. I got mine at a local dress shop. Just call local places and find a price. If you're in the US and live near a Ross dress for less they even have beautiful gowns for under $30.