Gas prices have risen slightly in Montana over the past week.GasBuddy.com reports that average gasoline prices in Montana went up 0.9 per gallon in the last week and are averaging $3.09 per gallon as of Monday, March 24, 2025.Ga s prices are 1.7 higher in Montana than a month ago, but are 45.57 per gallon lower than a year ago. The national average price of gasoline jumped 6.3 per gallon over the last week to $3.08 per gallon, which is 1.6 lower than a month ago.GasBuddy.com reports the cheapest gas in Montana was at $2.88 per gallon on Sunday, while the most expensive was $3.69 per gallon. ...read more read less