Restrict Content Pro allows site administrators to create any number of membership levels that customers can register for. Membership level options are displayed on the registration page and customers can select the one they wish to purchase.
Each membership level can be given a price, an optional signup fee (one-time amount), an optional trial period, a frequency and period, and a user role that will be assigned to members when they register.
Customers can also upgrade and downgrade between membership levels at anytime. These upgrades and downgrades are prorated based on how much the customer has already paid and how much time is left in their current membership.