Studios are very popular in Romania, as far as I know.
When I started in this business I was recruited by a studio. It was basically like going to an office or any other job. I got to a big house at a specific time, I used an individual room they provided with all the equipment... I just had to get ready for going online... they gave me a very basic intro into what this was about... I don't know how much % they took from my earnings, I just had a set price in local currency per minute. I didn't last long there, my experience with them was not good at all!!... I just learned enough to be independent.
I know that some studios are more professional nowadays, provide you with and teach you all you need to succeed... if you choose to go and work from their locations they can take between 50%-60% from your earnings, If you choose to work from home (they will be your support when you need tech assistance, toys, lingerie, photoshoot, etc) they can take between 30-10% from your earnings.