Ames had the most expensive gasoline in Iowa last week. Triple A says the local cost for a gallon of regular unleaded was $2.78, $.11 above the statewide average of $2.67, which is itself $.07 higher than a week ago. The national average is $2.80. For another week, Iowa's cheapest gas is in Council Bluffs at $2.56 a gallon--$.09 below the state average.