My FFL does not charge me anything. Honest!
He's my gunsmith and doesn't charge anything for transfers in or out to any of his regular customers. He's been my Gunsmith from the first day I needed a repair on my first rifle. I travel 2 hours from home to get to him, and it's worth every minute. I deal with him at least once every couple of weeks with repair service or trades or transfers (I've bought a lot of guns lately).
However, I do make sure he is paid something "extra" on most of transfers he does for me. He gives me the "You don't have to do this" every time, but I'm feeling guilty if I don't.
