While King games are completely free to download and play, you do have the option to purchase virtual items in-game using the app stores e.g. App Store or Google Play.
It is essential that you protect your device to prevent unauthorized or accidental purchases on your account, especially if young children have access to your device.
You can protect against accidental purchases by setting a password requirement for all purchases made on your device. For more support please check our article on "How to restrict in-app purchases on your device".