Coins can be used to purchase boosters prior to starting a level. There are multiple boosters to choose from. When you purchase boosters, they will be randomly placed on the board at the start of the level.
Where do I get Coins?
There are multiple ways to get more coins. You can always purchase them in the Coin Shop, in addition to earning them by playing levels.
You can get coins by clearing levels. They are given every time you earn new stars! A reduced amount of coins are given when you replay levels that you have already cleared. You can also collect free coins from your friends from the top 3 players in Rankings. You will be able to collect 100 coins each, every 4 hours.