I only see experienced independent Dommes, and usually for longer sessions and I agree that established independent Dommes set their rates so that they are fairly compensated for their time and their skills.

There was one very well known Domme who's rates where well below what the market rate for someone with her skills and equipment. After several lengthy sessions I realized that she was very generous with her time. Given her already lower rate, along with her willingness to play longer than our scheduled time, I began tipping her after every session, usually just a flat $100. She told me it wasn't necessary but once I insisted she seemed genuinely surprised and appreciative.