No, we do not charge per-user fees. All fees are on a per-App basis. Therefore, you can invite as many colleagues as you would like to your Account to help you track and analyze your search & competitor data.
We don't have contracts for our plans. In certain cases, we will have a negotiated a contract with our large enterprise customers who have a large numbers of apps that they need us to track and analyze. For further inquires, just drop us a line at firstname.lastname@example.org.