Cooperative experiences
I've belonged to two in the past and am currently a member of one today -all art co-op's. The first one wanted an annual membership plus a number of hours each month to staff, and then took 40% of sale price. I didn't live locally, so I was supposed to find someone to take my place each month, or pay a premium for membership. This lasted one year.
The second was in a very good location but wanted almost $200 per year for membership. They also wanted 40%. I tried it out anyway, even though it was further away from home than the previous one. Wasn't worth the effort.
The one I belong to now is where my turning club meets. The membership is only slightly more than our club's, but the people are nice and easy to get along with. They want 35%. They've increased the size of the 'gift' shop, and several members have pieces in it.
The interesting thing is that the consignment rate at the six or so places I have pieces in is all 30%. They don't have membership dues, and I've never had any problems otherwise with them. Other than my current one being where we meet, I probably wouldn't be interested in joining another.
If you're really serious about opening a turning co-op, I'd strongly suggest doing a thourough market analysis and making a business plan first. If you don't have strong sales, then your members will have to pay the rent and expenses. I thought the second one I joined was in an excellent area for sales, but I was wrong. Turns out they really don't do that much in annual business at all!