Atlanta has tried a lot of things at its two dances (!). One of them uses sliding scale, and it strikes me as a good way to go for many groups. Sliding scale avoids the need to define categories like "student" or "minor" and to just say, use your heart. It has not been abused as far as I can tell. The other dance uses $10/event--a nice, simple round number that I hope covers the costs.
The older and bigger dance tried an annual subscription a few years ago, while I was on the steering committee, and it was not continued after the initial one-year experiment. I do not have the info on hand to say exactly what did and didn't work, though I know there are polls and financial analysis that are floating around. I better not reconstruct it just from memory.
It isn't happening any more, but another group named Reframed offered the best subscription approach I've ever seen. The subscription would grant access to every event the organizer put together, which included a weekly contra dance and also thirteen other dances at one extreme. An individual event would either be free or would cost about $10, and I think the monthly subscription was around $40, but I can't remember for sure. The simplicity of it was wonderful for everyone involved, and it seems like it gave the organizer the opportunity to do a lot of experiments in both the dance line-up and in the role definition of quasi-volunteers within the group.
Reframed definitely had--has, I suppose--that club-like feel that I see mentioned in other posts on this thread. People hang out on the Discord with each other, and the subscribers would sometimes go to an event almost every day of the week. So it was quite the social hub for many of the members. Also, it struck me that these highest attendees were not at all moochers but were more like volunteers doing a lot of free work. When they would go to an additional dance or two a week, they don't really cost anything since they wouldn't have gone if the subscription didn't exist. Meanwhile, they do a lot to help out, including helping out the new dancers. That factor is important to consider for a subscription and makes it not as simple as ticket revenue minus operating costs.
Lex Spoon