BuddyPress.org

Here’s what you do:

Install s2member, and then in s2member settings go to General Options > URI Access Restrictions. If you add /groups/ as a URI fragment, all URLs with /groups/ will be restricted to logged in users. If you add /groups/create/ then anyone can see groups but only logged in users can create new ones, etc. You can do the same thing with /activity/ and /forums/.

I wrote up a really detailed article about integrating s2member and BuddyPress over here: http://www.buddyboss.com/how-to-set-up-recurring-billing-subscriptions-in-buddypress/