The cost per gallon of gas in the Gainesville area increased this past week slightly to $3.98 after prices jumped 15 cents nationally the week before. According to AAA’s weekly report released on Thursday, the Gainesville area saw the price per gallon edge up from $3.94 to $3.98. The national average for a gallon of regular gasoline is the same as it was last week: $4.09. Thursday’s national average for a gallon of gas is $4.09, which is up 25 cents since last month’s $3.84. In the Gainesville area, last month’s price was $3.79 per gallon, and last year it was $3.12.