fee-based system; billing system
Refers to a system where users are charged a fee, often used for online services, games, or subscriptions.
This app uses a fee-based system and costs 500 yen per month.
In fee-based online games, you need money to buy items.
usage-based billing; pay-as-you-go system
Compound of 課金 (かきん, 'charging a fee') and 制 (せい, 'system').