Jester David
Hero
It just needs to be something worthy to the clerics. Or the church's clergy, who may not all be clerics.
Imagine if one of the deacons or other members of the hierarchy needs something done and can't ask the clerics he commands because it's iffy. If the PCs do the task, the restoration is their reward, but the great cost also buys their silence. And the church official just orders a cleric to cast the spell and works out the cost in the church's books.
It could be something as mundane as high-jacking the supplies of a rival church, taking care of the deacon's bastard child, removing a problem individual, silencing a heretic, or getting some supplies from the black market. Anything that is better off the books.
Imagine if one of the deacons or other members of the hierarchy needs something done and can't ask the clerics he commands because it's iffy. If the PCs do the task, the restoration is their reward, but the great cost also buys their silence. And the church official just orders a cleric to cast the spell and works out the cost in the church's books.
It could be something as mundane as high-jacking the supplies of a rival church, taking care of the deacon's bastard child, removing a problem individual, silencing a heretic, or getting some supplies from the black market. Anything that is better off the books.