The Marshall Plan - For four years beginning in 1947, the United States pumped $12.7 billion in economic and technical assistance into Western Europe to help in recovery after World War II. Inflation adjusted cost: $115.3 billion.
Louisiana Purchase - In 1803 acquired 828,800 square miles of French territory for $15 million. It encompassed portions of 15 U.S. states: Arkansas, Missouri, Iowa, Oklahoma, Kansas, Nebraska, parts of Minnesota that were south of the Mississippi River, most of North Dakota, nearly all of South Dakota, northeastern New Mexico, northern Texas, the portions of Montana, Wyoming, and Colorado east of the Continental Divide, and Louisiana west of the Mississippi River, including the city of New Orleans. Inflation adjusted cost: $217 billion.
Race to the moon - On Christmas Eve 1968, Americans tuned into an extraordinary sight: a live telecast of moon's surface as seen from Apollo 8, the first manned spacecraft to orbit the moon. Nearly seven months later, Neil Armstrong was the first man to walk on the moon. This was the culmination of a $36.4 billion race to the moon that began with the Soviet Union's launch of Sputnik in 1957. Inflation adjusted cost: $237 billion.
S & L Crisis - The savings and loan crisis of the 1980s and 1990s was the failure of 747 savings and loan associations that cost U.S. taxpayers $153 billion. Inflation adjusted cost: $256 billion.
Korean War - After negotiations ended between North and South Korea in 1950, the United States intervened and escalated the Korean War that lasted three years and cost us $54 billion. Inflation adjusted cost: $454 billion.
The New Deal - At a cost of $32 billion (estimated) the New Deal was "the name that United States President Franklin D. Roosevelt gave to a series of economic programs he initiated between 1933 and 1936 with the goal of giving work (relief) to the unemployed, reform of business and financial practices, and recovery of the economy during The Great Depression" [source]. Inflation adjusted cost: $500 billion (est).
Invasion of Iraq - Also known as the Second Gulf War or Occupation of Iraq, the invasion of Iraq is an ongoing military campaign which began in 2003. It is led and largely composed of U.S. troops. To date, it has cost American taxpayers $551 billion. Inflation adjusted cost: $597 billion.
Vietnam War - The war or conflict occured in Vietnam, Laos and Cambodia from 1959 to 1975. The United States escalated the war in 1965 by increasing the number of deployed Marines from 3,500 to 200,000. In addition to the many lives lost in the proxy war, it cost the United States government (taxpayers) $111 billion. Inflation adjusted cost: $698 billion.
NASA - The National Aeronautics and Space Administration is an agency of the United States government. In addition to being responsible for our space program, the agency is also responsible for long-term civilian and military aerospace research. Some of the agency's programs include Skylab, the space shuttles and space exploration missions like Galileo, Voyager 2 and Pathfinder. Each year since 1958, the United States Congress passes a Federal Budget which includes funding allotted to NASA. To date NASA has been given $416.7 billion in federal monies. Inflation adjusted cost: $851.2 billion.
All nine of these events have a total inflation adjusted cost of $3.92 trillion. And each was a bargain compared to the recent economic bailouts. Including the Citibank bailout, the total cost to American taxpayers is $4.6165 trillion [source]. That's right. The bailout costs more than the Marshall Plan, Louisiana Purchase, race to the moon, S&L Crisis, Korean War, the New Deal, Second Gulf War, Vietnam War and NASA ... combined.