a peculiar commodity, because it is an attribute of living persons, who own it themselves in their living bodies. Because they own it within themselves, they cannot permanently sell it to someone else; in that case, they would be a slave, and a slave does not own himself. Yet, although workers can hire themselves out, they cannot "hire out" or "lease" their labour, since they cannot reclaim or repossess the labour at some point after the work is done, in the same way as rental equipment is returned to the owner. Once labour has been expended, it is gone, and the only remaining issue is who benefits from the results, and by how much. Labour power can become a marketable object, sold for a specific period, only if the owners are constituted in law as legal subjects who are free to sell it, and can enter into labour contracts. Once actualised and consumed through working, the capacity to work is exhausted, and must be replenished and restored. In general, Marx argues that in capitalism the value of labour power (as distinct from fluctuating market prices for work effort) is equal to its normal or average (re-)production cost, i.e. the cost of meeting the established human needs which must be satisfied in order for the worker to turn up for work each day, fit to work. This involves goods and services representing a quantity of labour equal to necessary labour or the necessary product. It represents an average cost of living, an average living standard. The general concept of the "value of labour power" is necessary because both the conditions of the sale of labour power, and the conditions under which goods and services are purchased by the worker with money from a salary, can be affected by numerous circumstances. If, for example, the state imposes a tax on consumer goods and services (an indirect tax or consumption tax such as value-added tax or goods and services tax), then what the worker can buy with his wage-money is reduced. Or, if price inflation increases, then again the worker can buy less with his wage money. The point is that this can occur quite independently of how much a worker is actually paid. Therefore, the standard of living of a worker can rise or fall quite independently of how much he is paid—simply because goods and services become more expensive or cheaper