Why you shouldn't make in-app purchases on an iPhone
Apple charges a fee for in-app purchases made on its App Store platform. This fee is typically a percentage of the sale, usually 30% which is why Youtube Premium which would typicall cost $11.99 costs $15.99 purchased in app. This means that when an app or subscription service is purchased through the App Store, Apple takes a percentage of the sale as a commission. This fee is applied to almost all in-app purchases made on the App Store, with some exceptions for certain types of transactions such as charitable donations.