How did gas prices with x*x.9 a gallon get started?

Question

How did the U.S. get to the point where gasoline is for instance $3.959 with that extra nine-tenths added. Why isn't it rounded off to a full number like $3.96?

Answer 1

When gas cost 29 cents a gallon in the '50's and '60's, gas stations used this ploy to make gas look less expensive. Lets say 29 cents vs 29.9 cents per gallon. Your eye sees it's under 30 cents, but actually .9 cents a gallon at this price level is about a 3.3 percent difference. With todays prices hovering around 4 bucks a gallon, that .9 cents a gallon difference is insignificant. It was just an advertising gimmick to fool the consumer.

Answer 2

a way in fooling your paying 399 a galon insted of 400