You can record a customer's usage and bill for it at the end of a subscription period by using metered billing.
Metered billing is useful in cases where you want to charge your customers a granular amount based on their consumption of your service during the billing cycle, instead of explicitly setting quantities. For example, if you are running an email-based SaaS business, you can track your customers' API calls, then bill them for the total number used at the end of each month.
Usage-based billing with subscriptions (Stripe Docs)