As of October 15, gasoline prices in Montana are unchanged in the past week, averaging $3.01 per gallon according to GasBuddy.com. Prices were 44.7 cents per gallon higher than the same day one year ago and are 4.9 cents per gallon higher than a month ago. The national has increased 6 cents per gallon in the last month and stands 42.5 cents per gallon higher than last year.