I am "repaid" in effusive goodwill. I am rewarded with affection, friendship, the satisfaction of a task done well, and the opportunity to be both creator and spectator. And sometimes they buy me dinner or a video game.
I spent this past week with my fellow GMs and players, visiting the locations from two of our (modern day) campaigns, talking about our games and characters. We improvised more RP during our car trips and evening hangouts, poked fun at one another, and enjoyed true camaraderie.

How can I charge my dearest friends even a single penny, when they have given me so much of greater value?