The fee for divination

Numbers 22:7 - The elders of Moab and Midian left, taking with them the fee for divination.

I wonder how much the fee for diviniation was. Did it depend on who the diviner was? Was a diviner exactly the same thing as a prophet? A seer? Did they each set their own rates? Was there a standard fee schedule? Did it depend on how important the task was? Two bulls and a sheep for cursing your enemies? A pair of doves to find out what the weather would be tomorrow?

This fee was going to be paid to Balaam. Apparently Balaam was known as a diviner. I wonder if he had been called upon for anything like this before. Was divining his only source of income? If so, I wonder how often he had to be hired in order to survive. Did he have a reputation as a good and reliable diviner? Were there bad, unreliable ones?

It's interesting that divining or prophesying came to be associated with a fee -- almost as if you could simply buy your future. I wonder if people who pay for baptism -- a payment which is not necessary -- are thinking along those lines. I wonder the same thing about those who charge fees for them.