Usage based billing is a legacy feature, and is not available on new subscriptions. Pay As You Go is our replacement for usage based billing. For more information, see our Pay As You Go documentation.
On legacy Creator, Pro, Scale and Business plans, you have the option to activate usage based billing. This allows you to pay for additional credits once you've used all the credits in your monthly quota.
Usage based billing offers a fixed price for each additional 1,000 credits used over your limit. The cost of these credits depends on your plan, and will be displayed when you enable usage based billing for your account, prior to confirmation.
On eligible plans, usage based billing can be enabled from your Subscription page.
Additional credits are billed at the end of the billing cycle, or when the outstanding balance exceeds 2 times the subscription price.