I don't have any scientific data on this, but I would say the most common thing in the US today is for the couple to pay for the wedding themselves, perhaps plus some contributions from one or both sets of parents. Back in the 19th and early 20th centuries, it was typical for the bride's parents to pay for the wedding, but remember that for the vast majority of people weddings were a LOT smaller and less expensive in those days. Ceremony in a church or courthouse, reception in the parlor at home, with cake and punch. No limo, no fancy dinner, no dancing. But now, most people getting married - men and women alike - have their own jobs, their own incomes, and may even own their own homes. They aren't going straight from their parents' house into married life. It is expected that the couple will have a wedding that they can afford to pay for, without requiring anyone's parents to foot the entire bill.