Gas prices in Maine dropped six cents per gallon over the past week, according to GasBuddy.The average price for a gallon of gas in Maine as of Monday is $2.68 per gallon.GasBuddy said the cheapest price in Maine is $2.49, while the most expensive is $3.05.Prices in Maine are 13.3 cents per gallon lower than a month ago, yet stand 21.4 cents per gallon lower than a year ago.The national average price of gasoline fell 7.1 cents per gallon in the last week to an average of $2.73 per gallon.GasBuddy said prices are down across the nation because concerns that tariffs could slow economic growth are causing oil prices to fall.