The price varies by edition and the license system of the software is based on the number of admin users required. An admin user account is a user that would be able to log in to the admin area, create/manage articles, and be an admin or author. They include Writers (Authors), Editors, and Superusers. The license restriction is on the number of admin user (staff login) accounts that can be created to log in and update your knowledge base. There is no limit on the number of end-users that can access the public area of your knowledge base.