The average gas price in Michigan is 7¢ higher than last week. Triple-A Michigan says it is now at $3.37 a gallon, up 39¢ in the past month and 13¢ higher than last year. A 15=gallon fill up now costs $50 on average in the state. The highest prices in Michigan are in Jackson at $3.40, while Traverse City’s $3.33 is the lowest average. Benton Harbor’s $3.35 is the third-lowest in Michigan.