I created a speedrun game page. Where can I find an audience for this game? (Maybe moderators, too.)

Only add trusted and active runners as moderators to a game. You shouldn't add people randomly. If you want to promote your game, I recommend making a post on the advertisement thread, which is a thread where people can post advertisements for games that they run.

Is there a fee?

There is no fee

Thank you. How do I find active players to become moderators?

As @Merl_ said, only add trusted or active runners as moderators to a game. That means, if there are no active runners in the game, you don't need to worry about adding extra moderators.

Ah, sorry, I misunderstood.