The price of oil drops to 90 dollars per barrel while war talks inspire optimism -. Traffic lights. Oil prices fell to $90 a barrel amid hopes for talks to end wars in the Middle East and Ukraine, though analysts are trying to temper that optimism. Against the backdrop of sharp drops in oil prices, the price of gasoline in the United States fell below $4 per liter for the first time since July. According to the American Automobile Association (AAA), the average price of gasoline is now $3.9788 per liter.