I had an agency who I've done sporadic work for over a number of years query a cost the other week.
She said "is that after our 10% or before". what 10% ? I replied.
"Are you not in our scheme then" she said. "No, but your in my scheme" I replied."
"What scheme is that?" she says. "I give you a fair price, to do a good job, you say "yay or nay" if you say yay, then that's what you pay, if you say nay, you find someone else to do the job" It's quite simple really.