When building your campaign, you have two options for how you’d like to be billed, one for single-flight campaigns and another for ongoing campaigns, also called a subscription campaign.
For single-flight campaigns, you’ll set both a start and end date with either a total or daily budget. If you’d like your campaign to renew as a subscription, mark the checkbox above the end date box. In that case, you’ll set only a start date and a daily budget. Subscription campaigns renew automatically every 7, 14 or 30 days. You will select which billing interval you'd like when you purchase the campaign.