Немного из другой области, но суть та же:
Charging a customer on how much they use the product or service is a new concept for many businesses and is a key strategy for companies in the Subscription Economy. This concept is called usage based pricing, which bases a charge model on the consumption of a billable service or resource. https://www.google.ru/search?newwindow=1&hl=en-RU&authuser=0...