There is no intrinsic value to any product or service, according to the professional economists, only what it will fetch in the market place. Before Marx, the most clear sighted economic thinkers, including Adam Smith, believed that all commodities had intrinsic value and that what gave them that value was the fact that they were products of human labour. Commodities are things destined not for immediate consumption by the producers but to be bought and sold.
Every commodity has two elements to it.
Unless all commodities share something in common regular exchange would be impossible. But as they all differ in shape, size, volume, colour, weight etc., it cannot be the physical quality or use value that allows them to be measured by a common standard. It certainly does not. So what determines the general price, the average price when, over time, all the fluctuations of the market are taken into account. Marx, like the bourgeois political economists before him, concluded that the key factor is human labour.