Paid Membership Pro is one of the best plugins a user can use to transform their WordPress website into a Membership site. With it, you can restrict some or all the content of your website and decide who can view it based on which Membership Level they purchase or sign up for. It is one of the few plugin companies that I work for as a Support Engineer at Paid Membership Pro and my job is to help users solve all sorts of issues or queries they may have. The greatest thing about working as a WordPress plugin support engineer is that I get to learn a lot about WordPress everyday and I also get to help people while I am doing it.
For more information check out: https://www.paidmembershipspro.com/