As an Admin, when you navigate to your Manage Users page, you will find your Current Users amount. This number includes all billable users that have been added. Billable users are anyone with the role of Admin, Manager, Customer Service, and SalesPerson. This does not include Customers.
Also, once you have reached a number beyond your contracted amount, you will see a message pop up when you view the Manage Users page.
When you are beyond your contracted amount and you go ahead and select Add User, you will be asked if you want to continue knowing it may result in additional charges.
NOTE: This is not including the B2B users that you might be wanting to add to your site.
If you have any additional questions, please contact firstname.lastname@example.org