Gasoline is now officially cheaper than milk in the U.S. Prices look set to drop below the $3 mark on Friday thanks to October's plunging oil prices. The average price of gas across the states has hit a four year low of $3 dollars a gallon, while the price at the pump fell 33 cents from September to October. Drivers in South Carolina and Tennessee are seeing the lowest prices, with an average of $2.75 a gallon. New Yorkers are paying the most, at an average of $3.37, but that's still down 22 cents on last years prices. Many excited drivers have taken to social media to share pictures of their gas station signs, showing prices dipping below the $3 mark.