When I was in High School in the late 60s, gas was $0.36 for premium. $0.28 when two stations would get in a price war.
I drove a '68 Camero SS with a 3/4 cam, bored and stroked and a fuel block that fed dual 4 barrel Holleys.
We got 8 to 9 MPG if we drove easy, 5 to 6 MPG if we got on it, which we always did.
Like Popper said, $10 would fill up the car (12 gallons), pay for dinner at Jamles (a sit down high end hamburger joint in Dallas) and get two tickets, popcorn and drinks at any movie house in Dallas.
Man, we were living high on the hog back then.
My buddies drove Mustang Mach 1s, Chevelle SSs, Judges, Mustang GT Fastbacks, none of which were stock.
We were invinsible and bullet proof!
I don't know how we lived thru it!