Put information in the monthly newsletter. Help writing a support letter. Requiring a certain percentage of the cost to be paid by the participants. Flyer inserts in the church bulletin. Call attention to those that get involved in local ministry when they return or decide to go long term as a result of going short term.
Penny drives Outside the local church or both.
Give people a few different versions of a fund raising letter on disk so they can personalize it easily. Don't limit the letters to only Christian friends and family. Car Wash Idea - Sell car wash coupons ahead of time. Host an Easter brunch or a Mother's Day brunch. Car-hopping for tips.