If you finding the best casual mobile game then you should play Coin Master. Then using those coins, you need to build your base and upgrade them to higher levels.
Here you need to collect coins by a slot machine. It is a base-building game, available on Android and iOS.
4.2.1 How you can get new spins on Coin Master?.4.1.2 Win Shields and Defend the Village.4.1 Spin the Slots Machine Wheel to Earn Loot.