I've been playing this game for about a month now, and have made it to level 179 without spending any in real time money. It's really difficult after level 50, and you have to spend a lot of coins on powerups to help you pass the levels. After each level, you are only awarded 10 coins, and the powerups are x5 more than that. The creators of the game should at least give 40 coins for passing a level. This game is promoted to be stress-relieving, yet it's the complete opposite.