heres the games scheme, you play it a bit and think wow this is nice, you get a free character every 30 minutes, oh now an hour, oh now two, oh now six and so forth
then it starts flashing "win free money" and you have to watch an ad, or you buy each character for a reasonable $1, when you can get an app for that much money, but no, you want your character which is a glorified skin to be all yours.