Budgeting for the Wedding Party
Before you ask those attendants to be part of your day, it's important to take a look at your budget. While the bride and groom are not responsible for paying for the attire of their wedding party, you still have to consider your finances.
At the very least, each attendant means a bouquet or boutonniere, a meal at the rehearsal dinner and at the reception, transportation expenses to the reception, and a gift for participating.
Then, too, it's important for the bride and groom to think about how expenses may add up for their attendants. Each attendant must pay for the dress or the rental tux, special shoes, and accessories. There may be transportation costs and possibly even hotel stays.
Attendants may have to miss work to attend the events or at the very least, time to attend rehearsals and so on. Therefore, it's important for the bride and groom to carefully look at budgets — both theirs and those of their prospective attendants.
Fact
Traditionally, there is a ratio between the number of attendants and the total number of guests who are invited to the wedding: one bridesmaid and one groomsman for every 30 to 50 guests. When it comes down to it, it's up to you. You can have 20 attendants or none at all.

