Traditionally, the bride's family pays for the bulk of the wedding, with the largest expense most likely being the wedding reception. The other wedding expenses are customarily divided between the bride and her family and the groom and his family.
In addition to the wedding reception, tradition states that the bride's family is also responsible for paying for the invitations, the bride's dress and accessories, most of the flowers, all photography and videography, the groom's ring, music for the church or other venue for the wedding ceremony as well as the cost of that venue, transportation to and from the ceremony and reception, and the bridesmaids' accommodations.
The groom's family has fewer expenses related directly to the wedding, but the groom and his family are traditionally responsible for paying for the rehearsal dinner as well as the honeymoon. In addition, they are expected to pay for the bride's engagement and wedding rings, the groom's attire, the bride's bouquet, corsages for mothers and grandmothers, boutonnieres for men, the groomsmens' accommodations, the marriage license, the DJ or band at the reception, and the liquor at the reception.
Additional expenses for both families include any pre-wedding engagement parties, the bridesmaids' luncheon and the bachelors' dinner.