In PokoPoko, there are in-app purchases that can be made to purchase in-game items.
But you can set your device settings to avoid any accidental purchases.

1. Go to [Google Play Store] on your device.
2. Go to [Menu] on the top left hand corner.
3. Select [Settings]
4. Select [Require authentication for purchases]
5. Select the option of your preference.

A detailed guide on how to change the settings of your in-app purchases is available here:
Require a password or authentication for purchases