Here is the workflow of how the app will (hopefully we can do this) flow:
Question: We just want to bill for each time the shop owner plans to create the product using our app, and not using a time interval such as 1 month, or 1 year etc. Can we still do this using the Recurring Billing or do we need to use the One-Time billing options?
I tried to test it locally but I got and error trying the confirmation_url:
Your plan 'development' cannot be charged through the API.
You can use the one-time billing for this. Once 7 days ticks by the clock in your app, the next time a product is created, you create a one time charge. You're really treading in shark infested waters doing this though. What happens if a merchant creates a second product before they accept the first charge you've created? You can only have single one time charge I think... until it is accepted, you'd probably be trying to create them to no avail. And since it can take a minute for a product created in Shopify to show up in your App, that gives them a minute to create a second or third product. So then they try to access your App with 3 products created and one onetime charge. Huh? You try it.. see what happens. Maybe it'll all work out.