Is there a way to configure spark for pay per use, like you 100 credits and use them whenever you like. I know I can refactor Spark for this but I was looking for the simplest solution.
I am currently using the following approach: users register their credit card using Stripe (or Braintree) in the settings page. Next, they can start subscriptions that will generate credits every month. Or, they can use single charges to get a certain amount of credits based on the amount of money they pay.