ball gown fabric?



A reenacting friend of mine invited me, quite last minute, to a ball that a unit in a near-by town is putting on. It's a week and a half away and I somehow need to come up with the time and money to create at least some sort of period ball gown. I can't afford silk, and wasn't sure what other materials would be appropriate. Any suggestions/advice? (Any sewing tips in general would also be useful, honestly. Unfortunately I'm a novice on all fronts here.)