BuddyPress.org

@satomom – No membership software. Just some basic PayPal subscription buttons and theme/function customizations based on whether a user is logged in or not. This method requires more oversight and maintenance (ex. if someone cancels their subscription), but it keeps everything simple for upgrades.

If you’re looking for a more robust solution, you might want to check out – https://wordpress.org/extend/plugins/s2member/