Yes I recall the 6 cent cokes and the refund when we turned the bottle in. In 57 I recall that near FT. Knox in a small town called Vine Grove, KY. We had gas wars then with 17 cent a gallon there.
13 cents was the cheapest I remember but Gasoline was only a quarter for several years and through the 50s it remained at 50 cents for years. Jimmuh put an end to that.
When you think about the price of a Coke at 5 cents and you could get 2 cents back for the bottle and there was no deposit so Coke company could not have been making much more than a penny a bottle profit. When they raised the price to 10 cents that would be more than a 200% increase in profit.