Billing mechanics
Prepaid credits
A balance a customer buys up front and draws down as they consume, sometimes at a discount to pay-as-you-go.
Prepaid credits are consumption bought in advance. The customer pays for a balance, usage draws it down, and the invoice shows what was consumed against what remained.
Credits improve cash flow and lock in commitment, and they usually carry a discount to list. They also create real accounting work: money received for credits is deferred revenue until the credit is consumed, and expiry policy determines when unused balance can be recognised as breakage.
The billing questions to settle before launch are whether credits expire, whether they apply to every charge or only some, and what happens when the balance runs out mid-period. See overage.