Gasoline is bought for the "future" so they pay X price which may be higher or lower than what it is now and when it gets time to use that gasoline, the price fluctuates according to the X price they paid back then when they bought it as well as what is happening now both in the world and in the country one is living in. That's why there are different prices at different brands and locations, etc. Too, there are state taxes on gasoline and many states tax higher than others.

Look at California taxes for example; that's why their price is higher than other states' prices (compare them to Texas): http://www.energy.ca.gov/gasoline/st...tate_2002.html