Pretty much, people won't buy on the 1st pitch - even if the stuff is awesome! In fact, it takes 7 go-arounds normally to make a sale - and that requires having a list. Well, this list would consist of an email and/or social media following, not sure of what's more effective.
Anyhow, for your forum, what methods of making money have you tried? Have you tried this way?
O.K., some popular websites for making a list are:
Who have used these? Myself, I have focused on Facebook, mainly because my music lesson stuff is text/audio, not video.