Sorry to be so terse.
I don't want to go into detail about the service, because it is a somewhat specialized kind of research.
Let me just say that I am paid between $25-100 each for each one I do, and I have been doing about $175 a week's worth, with some weeks up to $325. Over the last month, the amount of available work has dropped. Two weeks ago there was nothing, last week $20 and this week $125, with nothing else expected until possibly next week.
(I have other responsibilities which mean I cannot work for a week here and there, but my employer knew this when they hired me, and our understanding was that I would inform them of my availability, and they would assign me work at that time. I had been told that I could have as much work as I wanted to handle.)
Thank you for your help in thinking this through. What I am hoping to do is to establish a local service with a small number of regular clients. (They are currently receiving 3-4 times what they pay me for doing the work.)