Lists - where your contacts (we call them Subscribers) are stored. Each account can have an unlimited number of Lists. Subscribers can be added to Lists through:
Subaccounts - separate accounts that are tied to, and under, your primary Clearstream account. This is useful if you have a few large ministries or multiple campuses that need their own accounts but you only want 1 plan/bill.
Each monthly plan comes with a set number of Subaccounts. You can add Subaccounts to any plan for $20/mo/Subaccount.