Coins can be earned a few different ways:
 
1. Coin Claims: Throughout the day you'll have the ability to claim Coin/Credit sums from the Homescreen.

 

2. The Wheel, "Lock On", or "Magical Gift": Take a quick spin and collect Coins/Credits from the The Wheel (also known as Lock on and Magical Gift depending on the app).

 

3. Missions: Check out your Missions section, complete tasks, and earn Coins/Credits!

 

4. Free Currency: Want to earn some additional Coins/Credits? Check out the Free Coins/Credits section in the Store!