average u s gas prices have declined about 52 cents per gallon since hitting a 2015 peak price of $ 2 80 per gallon on june 15 the national average declined 26 out of 30 days in september for a total savings of 19 cents per gallonoday s national average price of gas is $ 2 59 per gallon which is eight cents less than a week ago and 84 cents less than a year ago pump prices are now 21 cents per gallon below the 2015 peak price reached on june 15