Even later on. I just watched the 1953 noir film The Big Heat with Glenn Ford. Twice a mixed drink served in a bar was 35 cents and each time the big tip of 15 cents rounded it up.
Lobby poster card saying was:
Somebody Made A Mistake.
They Forgot To Kill Me.
As late as c. 1975, Michelobs were still just $0.75 at the Fort Know O-Club. You gave the barmaid a dollar, and that was a nice 33% tip!