In the game's Shop you can find different PowerUp packages, which will help you achieve better performance during your games.
You will see four packages of different PowerUps, which will contain 5 units each. Inside each package you will see its price in coins.
At the top of the screen, you will be able to see your coin balance and the number of units you have for each PowerUp.
You will find the Shop in the second icon of the lower game options bar.