Open Studio is what they call it here. I used to call it open figure class, but it is basically through the school's facility and they offer a three hour classroom with the easels and horses for the workshops, a model stand for the model, a spotlight and a model. I believe the rate out here is $10-15 an hour.
Normally, when I was a student in Colorado, there were groups that might get together and hire a model and take up a collection to pay him/her. Normally it was nudes. Figure study and sketching to support anatomy studies, but the portrait studio is a really great innovation I was not familiar with.
The model had a timer and sits 20 with a five-minute break in the same pose all night.
I was in New York a year ago and the Art Student's League was exactly what it said, they had a place for students! We stopped into their open studio, which I believe was every afternoon at like 5 (I forget) and lasts 2 hours.
The way we pay at SAS is for $24 we get four tickets and can use them for the sessions. Students enrolled in a workshop are only $6 a session and single drop in price is $8. I think in New York we paid $10 for a morning, uninstructed studio but there were two models on either side of the room to chose from.
There is also a monitor in the League which was nice. There is nothing democratic about a group of artists! It is my opinion that the model should be the one who decides on the pose and set up because they have to hold it.
When I was in Colorado, the community college had one night of open studio. Sometimes it is not listed on the regular class schedule. I believe the University offered a few. To find them, hang out at bulletin boards... the ones with cork, not keyboards
in student unions or art stores. Long ago, I used to find them listed in the more or less counter culture newspapers etc..
Well, there is everything I know about open studio!