Paid Member Subscriptions is an easy to setup and use WordPress Membership Plugin. You can start getting paid almost instantly.
Instead of complicated setup pages, Paid Member Subscriptions integrates with your existing WordPress site and content and doesn’t force you into a predefined structure.
You will be able to create and manage member subscriptions, grant and revoke access to posts, pages, categories as well as custom post types based on the subscriptions your users have purchased.
You can download free version of the plugin here.