Yep, remember buying 4 gals (18 L) for £1 around 1967.
As a student in Warrington running first a 1935 Rover Ten and then a 1960 Rover 3-litre - both returning 20-22mpg.
This was easily possible on a student grant*! Try doing that nowadays!!

* Once upon a time, students' actually got these, in order to study. Would you believe that?