Currency

Objects used to pay for goods and services, backed by authority or by social consensus, are called currency. Currency is also useful as a measure of value and as a store of wealth. Metals have special qualities to be used as money. They require a specialized production, have a limited supply and are measurable, transferable, manageable, durable and recyclable.
Paper forms have many design possibilities, are manageable and inexpensive. Besides, they allow particular use conditions, personalization through writing and individualization through serial numbers. Coins, paper money and electronic money, as cards, are the most common means of payment today.