So in my app, users can subscribe to a monthly plan but on top of that they can add more features by paying extra per feature. Lets say the monthly plan costs $40/month. The user adds another feature worth $10. I want the user to be billed $10 right away and then add this $10 to his next months billing UNTIL he removes that feature so that the next billing period is again $40 instead of $50.
How can I go about it? I can setup monthly subscriptions but can’t figure out how to create these addons that the user can additionally buy and add to their plan. And then remove them if needed to from next billing cycle?