Gas prices in Michigan are up 9-cents compared to last week. AAA of Michigan says drivers are now paying an average price of $2.20 per gallon for regular unleaded. This price is 23-cents more than this time last month but still 61-cents less than this time last year. The most expensive gas price averages are in Marquette and Metro Detroit. The least expensive gas price averages are in Traverse City and Flint. Port Huron pumps are just a penny less than the statewide average, asking approximately $2.19 for a gallon of regular unleaded.