As a bridesmaid what do you have to pay for? Airfare, hotel,dress, and bachlorette party? and im in school.?

My friend is getting married and she is having the wedding in California. we live in Ohio and all the bridesmaids are still in school. She has asked us to pay for airfare, hotel, dress, and bachlorette party. Her family knows we dont have money. what do we do? Her family has money and we college students. Im honored to be in the wedding, but dont know if we can afford it.