from What has Government Done to Our Money?
What have we learned about money in a free society? We have learned that all money has originated, and must originate, in a useful commodity chosen by the free market as a medium of exchange. The unit of money is simply a unit of weight of the monetary commodity--usually a metal, such as gold or silver. Under freedom, the commodities chosen as money, their shape and form, are left to the voluntary decisions of free individuals. Private coinage, therefore, is just as legitimate and worthwhile as any business activity. The "price" of money is its purchasing power in terms of all goods in the economy, and this is determined by its supply, and by every individual's demand for money. Any attempt by government to fix the price will interfere with the satisfaction of people's demands for money. If people find it more convenient to use more than one metal as money, the exchange rate between them on the market will be determined by the relative demands and supplies, and will tend to equal the ratios of their respective purchasing power. Once there is enough supply of a metal to permit the market to choose it as money, no increase in supply can improve its monetary function. An increase in money supply will then merely dilute the effectiveness of each ounce of money without helping the economy. An increased stock of gold or silver, however, fulfills more non-monetary wants (ornament, industrial purposes, etc.) served by the metal, and is therefore socially useful. Inflation (an increase in money substitutes not covered by an increase in the metal stock) is never socially useful, but merely benefits one set of people at the expense of another. Inflation, being a fraudulent invasion of property, could not take place on the free market.
In sum, freedom can run a monetary system as superbly as it runs the rest of the economy. Contrary to many writers, there is nothing special about money that requires extensive governmental dictation. Here, too, free men will best and most smoothly supply all their economic wants. For money as for all other activities, of man, "liberty is the mother, not the daughter, of order."http://mises.org/money/2s13.asp