Web consultant and founder of Saint Valley Web Consulting. Helped over 80 businesses and organisations improve their internet presence
I am the owner of a web consultancy that has helped over 80 small to medium businesses reach the top of the search engines through well optimised websites, quality backlinking, citation building and social proofing.
Depending on the level of skill of the group members, I would try some affiliate offers from Clickbank. I have done some Facebook advertising of affiliate offers and I have found that photography courses and foreign language courses convert pretty well. In your position, where you have authority already as group admin, you should be able to convert a much higher percentage than I would using adverts. Look for a good course that has "rebilling" for recurring monthly compensation