The total utility which is yielded by the object in question. This is often referred to as its ‘ value in use’.
The quantity of some other commodity for which the object in question can be excanged. This is then referred to as its ‘value in exchange’. Thus, if the other commodity is money, the value of the object is price. If the other commodity is fur coats, the value of the object is the number of fur coats for which it can be exchanged.
Thus the ‘value theory’ could just as well be termed price theory, and consists of the analysis of what determines the equilibrium rates of exchange between commodities directly or between commodities and money.
Reference: The Penguin Dictionary of Economics, 3rd edt.