again... maybe it was just my luck... but i found an awesome dress at Ross for $17 one spring. Fit me perfectly. funny story behind it tho... my roommate had bought it before me but tried it on at home and discovered it was too short for her (long dress and she is really tall). I asked if I could use it for formal that semester but she had already returned it. So i went to ross and picked it up...
to get to the point: ask one of your sisters if they have a dress you can borrow. or try ross, marshalls, tjmaxx etc. we're college students... and if you aren't going alumn this semester, you will have plenty of other formals to go to... don't spend all of your money now if it isn't gonna be your last.
as for colors and styles... i am guessing lavendar or any shade of purple... that color fabric has been flying out of my store. i was watching the golden globes preview and they were mentioning stars wearing COLOR!... not just black.
stylewise: looking thru pattern books... i saw a lot of strapless and one shoulder deals. both short and long. halter dresses were also in there a lot.