The amount we’re shelling out to fill up the gas tank keeps rising. Triple-A Michigan puts the average price for unleaded regular at $2.78 a gallon, up 7¢ from a week ago. The price is down from the high for the year of $2.83 set on March 27. The most expensive fuel is being sold in Jackson at $2.86 a gallon, while the lowest average price is $2.71 in Marquette. The auto club says the average in the Benton Harbor/St. Joseph area is $2.79, a 14¢ jump in the past week. Prices are a little lower in South Haven, with GasBuddy putting the average at $2.71 along the shore in Van Buren County.