When you signup for the monthly subscription, the 99¢ signup fee gives you 330 image credits to start with. With every payment, you also receive an additional bonus of 500+ credits from our rewards program.
At that point, your account has a "positive" balance, and will count down until you reach zero. Then the system will begin keeping track of how many image credits have been used for the next billing cycle.
When you reach 3,000+ credits, your card will be charged for the current balance. The fraud-prevention threshold on your account will increase by 10,000 every time you make a successful payment, so that you will normally only be billed on your renewal date after your first month.
Every month, your subscription will "renew". If you've used over 3,000 credits, then it will charge the payment method you provided at signup. If you're below 3,000 credits, or have a "positive" balance, no charges will be issued. The cost per credit will always be the same as when you signed up. If prices rise, your subscription remains at the same pricing level.
There are no minimum charges, credits never expire, and there are no limits to how many credits you can use in a month (so long as payments are successful). You can, however, create "sub-keys" connected to your account, which can be useful for client sites, or for limiting the amount of credits that a site can consume in a month.
ExactDN: Each month, if you have an ExactDN subscription, you will receive 3,000 credits to use on the API. These bonus credits are "use it or lose it" and 1,000 additional credits will be awarded for each additional ExactDN site/zone.