It really depends, but once you have a new member, having cultivated them, you have them for two or three or more years if they renew. After a year they're adding to the group's bottom line. Then there's word of mouth, the more you increase your membership ranks, the more clout you've got. Up to 25 dollars per is usually an acceptable cost for acquiring a new member. You've worked all week, you've kicked back, gone out Friday night, you are in a good mood.
People seem to be ready to listen a bit.
Sunday evenings are next best. People sometimes get upset. Berkeley doesn't consider itself the center of the world, though. I don't think so. Berkeley at this point considers itself to be fighting a losing battle.