This app is available as a free version with a paid upgrade to use PRO functionality.
If you start a subscription, payments will be charged to your iTunes account at confirmation of purchase. Subscriptions will automatically renew at the end of the chosen period (1 month/3 months/12months) for the same price (= no price increases for existing subscriptions) until you cancel.
You can turn off the auto-renewal up until 24-hours before the end of the subscription period in your account Settings. When you cancel the auto-renewal process, access to the PRO features will remain until the end of the current payment period.
If you chose the „Lifetime Membership“ option, your access will remain available without further fees. This will include future technical updates, improvements to the app and new features. Still, payments will be charged to your iTunes account at confirmation of purchase.