Iowa gas prices have risen a nickel a gallon compared to last week. Triple A reports the average price for a gallon of unleaded gas in iowa is $2.19. That's $.02 lower than a year ago. The national average is $2.26, which is up three cents from a week ago. Diesel fuel prices are up a couple of pennies with a statewide average of $2.36, which is the same as a year ago, and $.08 less than the national average.