I think charging people to create games and letting anyone play for free is probably preferable to letting people charge users. Virtual currency is a great way

I think charging people to create games and letting anyone play for free is probably preferable to letting people charge users. Virtual currency is a great way to do this although you may consider doing it inside Facebook to accelerate that process. Making your own currency is tough unless you plug into a platform like Viximo. Commercial sponsors for content requires pretty enormous scale to be viable, the first 2 are probably better options.