Modern American paper money, including the trusty greenback dollar, is just a piece of paper that happens to be backed by the Federal Reserve until it is exchanged for goods and services. Although the purchasing power of the U.S. dollar has been significantly eroded over the past century, you can still get plenty of great things for a buck. A dollar will buy you a box of crayons, a cup of coffee, a daily newspaper and even a lottery ticket to give you the chance to win more dollars. Many restaurants feature special dollar menu items, and dollar sales at grocery and retail stores are favorite events for thrifty shoppers. When it comes to agricultural products and other commodities, however, a dollar seems less impressive. A greenback will only purchase .43 gallons of crude oil and one-third of a gallon of heating oil. A dollar compared to an ounce of gold is almost non-existent, purchasing less than .001 troy ounce of the precious metal.