Proportion of exchange between two items of consumer value is called the exchange value.Determining the amount of this proportion is so intricate in terms of different types of societies that its full discussion demands a detailed account; and it is this proportion which can be just or unjust. Discussion of its constituents, namely energy input, the number of spent hours, quality and quantity of the tools deployed and of the goods or services offered and one degree of their relationship, has been a focal point and an indispensable weight in an unbiased determination of their equitability or otherwise.
An individual, living in a progressive society with innumerable and complex wants, cannot unilaterally meet all his needs through Hiazat, productive activity or service. At the same time, consequent upon his specialized sphere of activities, a surplus of goods or services over and above his individual and family needs is inevitably generated. Therefore, a spontaneous ground for barter is provided, and it is used by the members of the society. It is noteworthy to mention here that an individual should always be barred through Hiazat from excessive accumulation of a good, which is scarce in nature, and from its barter for goods and services needed by him. This is meant to preclude the possibility of exploitation of others, who are not exposed to that particular good as he is. Under conditions of primitive barter system confined only to neighborhoods, the possibility of exploitation is precluded. For example, a villager may exchange his surplus eggs for a certain amount of meat with his neighbor. Or he may exchange a glass of superior cow milk for a glass of inferior cow milk plus two eggs with his neighbor. However, if barter becomes professional in nature and is placed in the category of "services", then it ceases to possess its simple characteristics to pose the threat of exploitation.
For example, a peddler may offer to his village folks two meters of cloth brought from t he city in return for 20 eggs, and thus a little profit is automatically earmarked for him. Now if he gets 2 1/4 meters of cloth for his 20 eggs from another cloth dealer, and exchanges the same for 25 eggs, then in the course of this barter, he has earned 5 extra eggs for consumption by himself and his family. Likewise, a provision store owner may get a profit of 150 tomans after 8 hours of work in a day. But if he gets 3000 tomans in a day, then it is an indication of exploitation; and the rates and his business activities must, therefore be regulated.
Therefore, we have seen that contrary to its initial stage, the barter system can be transformed into an exploitative affair in subsequent stages after it enters the domain of "services". A trader, a dairy product shop owner and their like perform a specific role in society, and because of that, they become entitled to remuneration; just like a laborer. However, utmost care must be exercised to ensure a just and optimum rate of return rather than unduly exorbitant profits rampant under capitalistic conditions. Today, all the countries invariably engage in bilateral trade with one another. The capability of a merchant, however, in concluding a useful deal with the outside world, does not justify his action of charging exploitative rates from the people just because he has such acquaintance. Meanwhilehe is entitled only to a modest rate of profit