Are bridesmaids supposed to purchase their bridesmaid dresses, and should groomsmen pay for their tux rentals? My friend says she has never heard of such a thing, and that I'm supposed to pay.
Wedding party members usually pay their own way when it comes to clothing -- the women buy their dresses and the men rent their formalwear. (And you should let everyone know about this financial responsibility before they accept the invitation to be in your wedding.) It's fine for the bride and groom to offer to pay for dresses and tuxes, but it's certainly not mandatory and most couples can't really afford to do so. What you can do is avoid going overboard and choosing costly bridesmaid dresses or formalwear. In the end, the proper thing to do is to keep your friends' budgets in mind when deciding what they'll wear.
Your Bridal Party
Choosing Wedding Attendants