Pricing is determined by the number of active users and customers in your system. The base prices allows begin with a the first block of 100 users and 5,000 customers. Each additional block will incur an additional fee. Usage is pro-rated. If you being the billing cycle with 100 users and in the middle of the month add 10 additional users, for example, the license will automatically upgrade and you will be billed for the last half of the billing cycle only. The reverse is also true if customers or users become inactive and it causes your license to drop to a lower block.