I have run a game on roll20 nearly every week for the last four years for free, which is fine and I have enjoyed doing so. I try to encourage the players I play with to take a turn at running a game, when we get to the end of one of the games I am running to keep the group going. However on most occasions everyone shrugs their shoulders and disappears, which means I don't get to have a go at playing. GMs typically bear all the financial costs of running a game on roll20 having to buy tokens, modules and pro level subscriptions, and invest their time and energy into creating a game. A better system might be where by the players have to purchase "chips" from roll20 for a small amount and then use these tokens to voluntarily tip the GM at the end of a game. The GM could use these "chips" to buy modules, tokens and content as well as use the "chips" to tip other GMs in games they might be playing in as players. I realise that this suggestion won't be popular with players who aren't GMs, but most players are getting a free lunch at roll20. Tipping the GM would be optional of course and the GM would be able to opt a game in or out of the tipping system.