I am trying to put together a site that has some payed content and need to see if any one has some ideas.

Most of the sites directories are article based run through k2, and can be viewed by registered members. but I want to have a few directories that are business listings and or classifieds where you would pay to post but viewing would be open to registered members. given the way k2 is set up with the user groups can this be dune. is there a way to resign user groups automatically rather than manually. i.e. if some one bought a subscription to post in a business listing for a year. I would like to have clear definitions between regular members and members who are paying to post content.

Has anyone had any luck with a subscription based component such as Ambre and juga, joomsuite members or others?