I attended the Fifth Amendment (later renamed Fifth Dimension) almost weekly, probably in 63 & 64. As I remember, it didn't cost much to get in & was somewhat negotiable. Whining, wheedling and bringing a group sometimes helped. I was totally broke in those days, and, let's face it, kind of a bum.
The list of performers I saw there would be very long.
Gary Eisencraft always insisted on singing a few songs before bringing on the main talent, and the crowd were openly whiney and impatient. He tell them, tough, you have to listen to me first. But really, it was all in good fun.