Average gasoline prices in Montana have fallen 0.5 cents per gallon in the last week, averaging $3.22/g on Monday, Feb. 6,, according to GasBuddy’s survey of 615 stations in Montana. Prices in Montana are 23.0 cents per gallon higher than a month ago and stand 16.2 cents per gallon lower than a year ago. The national average price of diesel has fallen 5.2 cents in the last week and stands at $4.60