Rewards for a DM? None that don't come out of the game on their own. If I'd only DM because somebody paid me to do it (in whatever currency), I'd not be motivated enough to make a good job of it. I consider myself as just another player at the table, if one with a slightly different role from everybody else. Like a goalie, I'm part of the team, and don't need special compensation that I don't get to score any goals. I'm doing my job because it's the most fun part of the game for me (although occasionally playing a PC is nice, too), because I'm the vastly most experienced at it (probably doing a better job with less investment of time than anybody else in my group), and because it's the part of the game that I'm best at (in comparison to roleplaying a single PC).
There you have my Tao of DMing:
DMing is a manifold art
You get to have all the power beneath moon and sun
Yet to wield it, you must give it up,
Dive in, become part of the group once more.
Not to elevate yourself, nor denigrate your desires,
Are you the DM.
Play with the other players, not against them
For indeed you are one of them.
Enjoy yourself. But not more than others.
And remember that your flaws
Will enrich the game
More than making none.
(not that I don't enjoy wielding the power, or making things difficult for my players once in a while. After all, they want me to DM, they better put up with what I feel like doing!)