Gas prices in Yakima up from same time last year. PORTLAND, Ore. (AP) -- The AAA auto club reports the average price of a gallon of gasoline in Oregon is $3.04. That's down 2 cents in a week, 23 cents in a month, and it's 24 cents lower than a year ago.But, it's 23 cents higher than the national average.Some metro prices from the AAA's Monday survey: Portland $3.02; Salem $3.03, Eugene-Springfield $3.03, Medford-Ashland $3.00.hat's down 2 cents in a week, 23 cents in a month, and it's 24 cents lower than a year ago. But, it's 23 cents higher than the national average. Some metro prices from the AAA's Monday survey: Portland $3.02; Salem $3.03, Eugene-Springfield $3.03, Medford-Ashland $3.00.