Per User or Seat Cost
You pay a fixed Odoo license cost for a seat per month. Currently, for the US market, it is $28/user/month. If you are a first-time Odoo Enterprise user, then you get the Odoo license cost at $24/month.
Cost for the Odoo Apps for your Organization
Odoo is a suite of business applications for every department in your business. You will choose the Odoo apps you want to use for your organization which is a fixed fee per month, not based on how many users need access to the apps.