No, not for a gallon, for half a tank!!
Good old P.I. Jim Rockford gassing up his gold Firebird while working a case. His fee? $200 a day plus expenses. Nowadays, the expenses would kill you. I'd insist my P.I. drive a Prius.
This must have been around 1976, when gas was 59 cents a gallon. So old Jimbo got 5.08 gallons of petrol in return, roughly what $22 would get you today.