Considering that Pokemon Go is being developed by Niantic Labs, there would be little IAPs (In-app purchases). After all, they did develop Ingress (another MMO) which as far as I can recall didn't have any ads and little to no IAPs. Then again, it was a long time since I played that game so I have no idea about the state of it now.
Anyway, it's still hard to tell how the Pokemons are going to be distributed around the world. However, I'm sure Legendary Pokemons will only appear as some sort of event in cities because I doubt anyone would want to head to the countryside just to catch Legendaries (minus National Parks of course). Needless, to say, I can't wait to play this game.
