I was in Tawas yesterday and in a two hour period the Shell station @ US23 & M55 went from $3.72 to $3.70 to $3.99. During this period a Admiral and Walmart stayed @ $3.69. I did tank at the Shell for $3.70. They will manipulate things to get the price up for the holiday weekend. Three price changes in two hours, and a 27 cent a gallon jump is gouging, plain and simple.