We run a monthly (more or less) ballad workshop. When we do a teaching session, we have a set of charges which takes account of members, non-members and concessions -- the aim is to cover room hire charges and photocopying. And we also run a raffle at each event (homemade chutney or marmalade, donated books or CDs etc) to build up funds for guest events.

And then periodically we have these guest events, for which we charge more -- although on the same sliding scale.

We're now into our 5th year and are endlessly encouraged by the goodwill of our core support, who seem to appreciate the opportunity to explore the great narrative songs -- lots of discussion and argument around motive etc.

So maybe the answer is to have a very specific focus for your group?