In-App Terms of Service:
All in-app subscription payments will be completed and paid through your connected iTunes account and may be managed under Account Settings after the initial payment for the subscription.
In app subscriptions to remove ads will automatically renew at the end of the monthly cycle.
Your iTunes account will be charged the renewal at least 24-hours before the end of the current monthly cycle.
Subscription payments are set to automatically renew unless deactivated by user at least 24-hours before the end of the current monthly cycle.
Cancellations are processed by disabling auto-renewal through your connected iTunes account.