For another week, Ames has the most expensive gasoline in Iowa. Triple A says Ames is the only metro area in Iowa where a gallon of regular unleaded is over $2.90--the local average is $2.93. Ames' price is only $.02 behind the national average of $2.95 a gallon. Statewide, the cost is the same as a week ago at $2.84. The lowest average price is in Sioux City, which is the only city in Iowa below $2.80 a gallon at $2.77.