(New York, NY) -- Motorists are paying more at the pump. The nationwide Lundberg survey finds a gallon of regular unleaded gasoline cost an average of $2.66 last week. Thats up 18 cents over the past two weeks as crude oil prices shot higher. The least expensive fuel in the country is found in Tucson, Arizona, where drivers are paying $2.24 a gallon. The highest in the lower 48 states is $3.06 a gallon in San Francisco. The most expensive is in Anchorage, Alaska, at $3.25 a gallon.