Editing Medium of exchange (section)

===Barter as the origin of money===
{{see also|Barter#Limitations}}
In a [[barter]] transaction, one valuable good is exchanged for another of approximately equivalent value. [[William Stanley Jevons]] described how a widely accepted medium allows each barter exchange to be split into three difficulties of barter.<ref>William Stanley Jevons, 1875. 'Money and the mechanism of exchange' Chapter 4 http://oll.libertyfund.org/titles/jevons-money-and-the-mechanism-of-exchange</ref> A medium of exchange is deemed to eliminate the need for a [[coincidence of wants]].

====Want of coincidence====
A barter exchange requires each party to a transaction to have something the other desires. A medium of exchange removes that requirement, allowing an individual to sell and buy from various parties via an intermediary instrument.

====Want of a measure of value====
A barter market theoretically requires a value being known of every commodity, which is both impractical to arrange and impractical to maintain. If all exchanges go 'through' an intermediate medium, such as money, then goods can be priced in terms of that one medium. The medium of exchange allows the relative values of items in the marketplace to be set and adjusted with ease. This is a dimension of the modern [[fiat money]] system referred to as a "[[unit of account]]."<ref>{{Cite journal|last1=KIM|first1=YOUNG SIK|last2=LEE|first2=MANJONG|date=2013-11-22|title=Separation of Unit of Account from Medium of Exchange |url=http://dx.doi.org/10.1111/jmcb.12066|journal=Journal of Money, Credit and Banking|volume=45|issue=8|pages=1685–1703|doi=10.1111/jmcb.12066|issn=0022-2879|url-access=subscription}}</ref>

====Want of means of subdivision====
A barter transaction requires that both objects being bartered be of equivalent value. A medium of exchange is able to be subdivided into small enough units to approximate the value of any good or service.

====Transactions over time====
A barter transaction typically happens on the spot or over a short period of time. Money, on the other hand, also functions as a [[store of value]], until what is wanted becomes available.