Unlocking features in the game like Characters, locales, and tricks will cost you the coins which you get by either earning them by performing dives or by spending real money. Every now and again the game will ask you if you want to watch a video, this is worth doing as you will be given 15 coins for doing so. Remember though that these coin earnings will go down the more advertisement videos you watch. You can get around this so you get the maximum 15 coins per video by closing the game and then re-opening it. Watching the advertisement videos can activate the magnet that allows you to collect more floating coins. To watch the advertisement videos just tap the 'Spin' menu and go to the bottom right side of your screen.