Question
Are agent and admin roles priced differently?
Answer
No, there is no difference in cost between agents and admins in Zendesk.
The owner can add or remove seats for the account. This will decrease or increase the possible number of agents or admins, see the article: Viewing and managing plan subscriptions.
For more information on the differences between the roles, see the article: Understanding Zendesk Support user roles.
Note: On Enterprise, you can customize agent seats through custom roles.