There are number of reasons why particular countries limit the free flow of goods and services on an international scale. The reason may lie in the sphere of politics, being tool to fight an enemy nation or which happens much more often, in the economic shphere, protecting country's industry agaist the competition of cheaper goods from abroad. Tariffs or duties imposed on the goods imported into a country, there are revenue tariffs , a form of income for the country's government ad protective tariffs, which are designed to protect domestin industry. TeensLikeItBig are calculated in such a way that foreign goods become more expensive than the domestin equivalent.