What are some free (or nearly free) places for groups of 20 or more people to meet regularly?

Our group conducts classes weekly using the private party room of a local restaurant. We don't have to pay to use the room, but the restaurant makes money on us from everyone ordering food. It's a good arrangement, but we're looking to expand, and this particular room has limited availability in that other groups have booked the room and the restaurant will not book the room on the weekends.

We only charge to cover the expense of the materials used in the classes, so we're not making the kind of money needed to rent our own building or anything like that. We wouldn't mind paying a little something to use a conference room, but finding affordable places like that are impossible. One local community center wants 30% of what we bring in right off the top.

We've tried book stores and coffee shops, but they haven't worked out from either a space, noise, or privacy standpoint. Any suggestions?

If there is someone in your group who lives in an apartment building, see if they can use the recreaction center. Usually, apartments rent them to residents at a very low rate, or in some cases, nothing at all, if you leave a check as a deposit and clean up afterwards. You have plenty of privacy. If there is a small fee, bring a pot luck dinner and let everyone contribute a portion of what they would have spent at a restaurant.

try a park with a private pavilion most r very inexpensive to enter and charge a nominal fee for the pavilion if any depending on the time of year you can have a BBQ or sak people to bring a pot luck

How about a school auditorium? It would be big enough for a large group, and I don't see why the faculty would have a problem with you using it after school or on weekends.

Library, church, or park and rec center. You can bring in your own coffee and some snacks yourself. Put a basket on the table asking for a small token from those who indulge so you are not out of pocket for these goodies.