You can cancel automatic renewal of your subscription through your device's app store:

On iOS, you can manage your app subscriptions through the Settings app on your device. Detailed instructions are available here.

On Android (Google Play), you can manage your app subscriptions through the Google Play store app or here. 

On Amazon Fire devices, you can manage your app subscriptions through the Amazon App Store by following the steps here.

You can cancel your subscription at any time. The subscription will continue until the end of the current billing period and then will not renew. You can choose to manually renew the subscription if you want to continue in future.

Please note subscriptions renew automatically at the end of the current period unless auto-renew is disabled at least 24 hours before that time.