I see now ...

  • Standard Edition includes all of the communication and collaboration applications, support for an unlimited number of user accounts each with 2 gigabytes of email storage, and it's free. If you don't already have an internet domain (like example.com), choose Standard Edition and we'll help you purchase one for $10.

  • Premier Edition includes all the benefits of Standard Edition, plus an uptime guarantee for email service, 25 gigabytes of email storage per user, integration APIs and phone support for critical issues. Premier Edition is $50 per user per year, but for a limited time you can try Premier Edition for free for 30 days.

Added emphasis -- looks like free is plenty
Can never figure out how the can afford this.
They don't hit you with adds or adds on a signature ... then that is amazing.