Create a consumable IAP called 'credits'. Allow the user to purchase them in quantity 1-100 each for $0.99. (Or sell them in discount packages.) Retain the number of credits the user has purchased. Allow the user to select a course and debit the user's credits by an appropriate amount based on course and subscription status.Because these are really 'non-consumable' IAPs you may need to create some method of allowing the user to restore their 'purchases' on other devices. You could use the user's iCloud key-value file for that.
Topic:
App & System Services
SubTopic:
StoreKit
Tags: