I found this gem in the The Knot magazine. I love it because it really shows that being in a wedding, although a huge honor, can also be a huge expense. It’s best to be straightforward with the numbers when asking someone to be in your wedding party.
Here are the estimates:

Shower……………………………………$50 - $100

Shower Gift………………………………$25 - $75

Bachelorette Party………………………$50 - $200

Dress/Alterations………………………..$300 - $400

Shower……………………………………$50 - $100

Shoes/Jewelry…………………………..$75 - $150

Hair/Makeup……………………………..$75 - $100

Wedding Gift……………………………..$50 - $150

Travel Expense…………………………..$200 - $1000

credit: The Knot Magazine