For example, the United States is a major consumer of coffee, yet it does not have the climate to grow any or its own. Consequently, the United States must import coffee from countries (such as Brazil, Colombia and Guatemala) that grow coffee efficiently. On the other hand, the United States has large industrial plants capable of producing a variety of goods, such as chemicals and airplanes, which can be sold to nations that need them. If nations traded item for item, such as one automobile for 10,000 bags of coffee, foreign trade would be extremely cumbersome and restrictive. So instead of batter, which is trade of goods without an exchange of money, the United State receives money in payment for what it sells. It pays for Brazilian coffee with dollars, which Brazil can then use to buy wool from Australia, which in turn can buy textiles Great Britain, which can then buy tobacco from the United State.
Third, one nation can sell some items at a lower cost than other countries. Japan has been able to export large quantities of radios and television sets because it can produce them more efficiently than other countries. It is cheaper for the United States to buy these from Japan than to produce them domestically. According to economic theory, Japan should produce and export those items from which it derives a comparative advantage. It should also buy and import what it needs from those countries that have a comparative advantage in the desired items.
Finally, foreign trade takes place because of innovation or style. Even though the United States produces more automobiles than any other country, it still imports large numbers of autos from Germany, Japan and Sweden, primarily because there is a market for them in the United States.
For most nations, exports and imports are the most important international activity. When nations export more than they import, they are said to have a favorable balance of trade. When they import more than they export, an unfavorable balance of trade exists. Nations try to maintain a favorable balance of trade, which assures them of the means to buy necessary imports.