“ Money Whether a product is fabricated as a commodity or not, it is always a material form of wealth, a use-value intended for individual or productive consumption. ”
 Karl Marx, Das Kapital (1885). copy citation

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“But how forms which belong in the sphere of pure changes of the form of value and hence originate from the particular social form of the process of production, forms which in the case of the individual commodity-producer are only transient, barely perceptible elements, run alongside his productive functions or become intertwined with them — how these can strike the eye as the huge costs of circulation can be seen from just the money taken in and paid out when these operations have become independent and concentrated on a large scale as the exclusive function of banks, etc., or of cashiers in individual businesses. But it must be firmly borne in mind that these costs of circulation are not changed in character by their change in appearance. (c) Money Whether a product is fabricated as a commodity or not, it is always a material form of wealth, a use-value intended for individual or productive consumption. Its value as a commodity is ideally expressed in its price, which does not change its actual use-form in the least. But the fact that certain commodities like gold and silver function as money and as such reside exclusively in the process of circulation” source