Campaign Manager automatically deducts your advertising charges from any promotional credit balance on your account as your ad campaigns start to spend. Once the promotional credit balance is fully used, additional charges are billed to your payment method.
Campaign Manager does not automatically stop your ad campaigns from running. This means that your account continues to accrue charges unless you end an ad campaign. You are responsible for any charges once the promotional credit is fully used.
Important to know
You can control how much you spend by setting a daily budget and end date for your campaign or ad set.