There are various ways to obtain free coins. These ways are:

• Opening the Area Chest
• Completing Bonus Levels
• Beating normal, hard, and super hard levels
• With the remaining moves at the end of a beaten level
• From events like Propeller Madness, Book of Treasure, Team Battle, Team Treasure, Team Tournament, Dragon Nest, Train Journey, Ocean Odyssey, Puzzle Break, Magic Cauldron, Mission Control, Mission Pursuit, Archery Arena, Balloon Rise, Pinata Party, Lava Quest, Hidden Temple, and Royal League.