Click on the red "Buy Online" button to view the different licenses and pricing options. Or call 1-800-275-9376 ext. 738 to speak with a sales representative if you would like to go over any specifics regarding pricing.
In regards to adding users for the @PrintByXerox app, there is no way to add users to a specific agent. The way you will add users is via the Xerox Mobile Print Cloud web portal:
The information you will need to set up Xerox Mobile Print Cloud for the first time is located in the Administrator and Troubleshooting guide starting in section 2 (page 2-1). If you start at page 2-1 and read through it, it will guide you through the entire process.