The Marshall Plan was an initiative launched in 1947 in which the United States gave a whole ton of money (about $12 billion back then, which is like $96 billion in today's money) and various kinds of other aid (like food) to countries of western Europe. The idea behind the plan was to make sure that those countries were able to rebound economically from World War II. This was important to the US because we did not want those countries to become poor because that might tempt them towards becoming communist.
The aid was also offerred to countries in Eastern Europe, but the USSR forced them to turn it down. I assume that we offerred it to them mainly for show because we surely knew the Soviets would never let them take aid from us.
Marshall Plan, Popularly referred by this name after George C. Marshall (1880-1959), an American Soldier and statesman who proposed it, was set up in 1948 by the United States to help the nations of Western Europe to rebuild their economies from the effects of destruction caused by World War II. The official name of the plan is the European Recovery Program.
Under this plan, the United States spent billions of dollars to rebuild war-torn western Europe. In addition to the direct financial help the plan helped the participating countries in their recovery by encouraging them work together cooperatively. As a result of success of Marshall Plan, by early 1950's most of the participating countries were producing more than the pre-war levels. Marshall played an important role in implementing this plan and was awarded the 1953 Nobel Peace Prize for this work.
Under this plan, the United States agreed to aid Europe if the countries would meet to decide what they needed. The work under Marshall Plan began in April 1948, with USA establishing the Economic Cooperation Administration (ECA) to administer foreign aid. Seventeen nations formed the Organization for European Economic Cooperation (OEEC) to assist the ECA and develop cooperation among its members. From 1948 to 1952 United States sent food, machinery, and other products to Europe, worth about 13 billion U.S. dollars.
The Marshall Plan formulated under the Truman Doctrine aimed to provide economic assistance to European nations that were in the midst of post-war reconstruction. The Americans also sought to use the plan as an attempt to contain the spread of Soviet influence on the European continent, especially in Eastern Europe. This was achieved through the establishment of economic ties with the US, which in effect would break any bonds these states had with the USSR. Policy-makers also sought to use the economic recovery of European nations as an outlet for the excess industrial output the American economy was generating.