Hi azaria567,
Be careful about not asking the regular parish organist, first, for permission to allow somebody else to play for a wedding. In some parishes, mine included, there is a written policy in the church bylaws that states (in part) "none but the regular organist on paid staff for this parish shall be engaged to play for any wedding, funeral or church services, without the express permission of the permanent staff organist."
My standard fee for a wedding starts at $175.00. If there is to be a soloist, that adds another $45 as it will always require additional rehearsal time, and in all cases, the soloist provides their own music and a copy for myself ... 3 weeks in advance. I always require a meeting with the wedding couple at least 6 weeks before the wedding to discuss music. Changes in music can be made, but no later than 2 weeks before the date, and only if they provide the music to be played.
My fee includes up to 30 minutes of Pre-Nuptial music ... usually the drone of the organ for that time is quite sufficient for most wedding people. I never ever play for receptions - I did that once, and that was enough ... not my cup of tea!