An interruption in supply and demand and economic warfare, coupled with unfair business practices in the US causes the price of fuel to rise. During the original invasion of Iraq, tanker traffic in the Persian Gulf was drastically cut for fear of losing ships and cargo. This caused a minor shortage of crude oil. OPEC only sales crude, it is refined (distilled) locally. In capitalist free markets, suppliers are allowed to raise prices during shortages, so that they can outbid other consumers when replenishing their crude. Unfortunately, OPEC realized that countries were willing to pay this extra price and refused to lower their price when pre-war supply was restored. OPEC denies this, but the US has captured documents that prove OPEC intentionally inflated prices. Now, because gas prices go up, it costs more for the shipping and trucking companies to do business. A large percentage of what you pay for a gallon of milk comes from the shipping cost of getting it to your grocery.