In this instance you are not really marketing the church, but instead, the groups that utilize the church facilities for their specific functions. Essentially, you would be paid by the folks that put on the dances, etc.. at the church and not the church itself. I've only done a few of these, and I charge them the same fee as anyone else and never had a problem.
PSR-S950, TC Helicon Harmony-M, Digitech VR, Samson Q7, Sennheiser E855, Custom Console, and lots of other silly stuff!
K+E=W (Knowledge Plus Experience = Wisdom.)