Help me dress like Bach or Mozart!

I have tickets for La Valse at the NY Phil on Halloween and I plan to wear a period costume. I'd like to dress like Bach—since he is my favorite composer—but I know that it's difficult now to find clothing in the style he wore without spending a lot of money. On the other hand, I could dress like Mozart, which would be a lot easier, since 18th century costumes can be had for cheap as long as you don't mind their falling apart after one wear (I don't). Links to costumes would be highly appreciated! Please help me annoy as many old people at the NY Philharmonic as possible!