It is currently possible to require approving users before they can login, this was implemented in mojoPortal 2.3.6.1.
But there is no ecommerce involved with that implementation. There is a planned add on feature on the Road Map, Site Membership Pro that will be designed for this purpose. It will manage user membership in roles for premium content based on their payment of membership dues. But I'm not sure when that feature will be available.
Best,
Joe