An Islamic principle is a belief in the free market. Islam views tangible goods with intrinsic value as money. Here are some examples of goods that can be exchanged for money: Dates, wheat, barley, salt, silver (as Silver Dirham), gold (as Gold Dinar), and silver. The six items—gold, silver, dates, wheat, barley, and salt—are taken from a hadith and were used as currency in the barter system. As a result, Sunnah money is sometimes referred to as the items described in hadith.

You can use paper money or electronic money as long as it is backed by one of these goods at a set exchange rate (in other words, the paper is essentially a contract stating that the bearer can redeem the paper for a set amount (weight) of that specific good). Most national currencies throughout the world were backed by gold until 1971. The paper could only be redeemed by governments; the regular person could not.

As long as paper money (fiat currency) is not used, the market determines the price of a commodity. The makers of fiat money, on the other hand, have the power to influence or change the price or value of goods (by virtue of the market law of supply and demand).