As far as I'm aware, in order to charge merchants for per-use apps, you need to create an AppSubscription first.One of the required fields of the AppSubscription is to have a maximum amount you can charge for that billing period.
However, if I were a merchant - at first glance this looks really scary:"What! they want to charge me $100??? Are they crazy??"Is there another way to get per-use like charging behavior without scaring my customers away?