Drag'n'Boom

You can play the whole game for free (if you don't mind ads every 3 levels or so), but with $1.99, you turn it into a premium game, and it's a steal for that amount. It will take you some time to get through all 50 levels—especially if you're trying to get every single coin and take out every single enemy. So, if you want to see how the Khaleesi of Game of Thrones felt while riding Drogon to battle, Drag'n'Boom is for you.