When two people each have items the other wants, both people can determine the values of the items and provide the amount that results in an optimal allocation of resources. Therefore, if an individual has 20 pounds of rice that he values at $10, he can exchange it with another individual who needs rice and who has something that the individual wants that's valued at $10. A person can also exchange an item for something that the individual does not need because there is a ready market to dispose of that item.
However, this isn’t always possible. For instance, you may have a $150 digital music player and want a small refrigerator worth $100. In this case, if both parties are certain of what they want and understand the difference in value, there should be no barterer’s remorse. Alternatively, you can ask for the mini-fridge plus $50 to make the trade – the worst anyone can say is “no.”