We need not waste much time over this point. Such a buyer will have in his mind a maximum offer determined in the manner just described. The collective value in use of the goods to be acquired, estimated in a sum of money whose exchange value, according to the subjective valuation of the would-be purchaser, is equal to this value in use, gives the maximum. The more items there are to calculate, the greater will be the maximum, reckoned as a whole, but the smaller will be the maximum of the single item, because in this case the value in use of the unit will be proportionally less (and the higher also will rise the exchange value of the money as consequence of the increased expenditure on the whole). If e.g. a person were willing to buy 10 goods at a shilling each, but were made by the seller to buy 20 instead, he would be able to give only a smaller price per item, as the larger purchase would bring with it a smaller utility, and at the same time the larger expenditure would be more heavily felt. At no time, however, will any purchaser -- and this is our most weighty proposition -- consent to pay anything but one and the same price for one and the same article, and that price will be the equivalent of the current "marginal item," say the 10th good in the case of 10 items, or the 20th in that of 20 items --always assuming that the market is an open one, and the buyer at liberty to purchase more or less according to his pleasure. If in any open market a price were demanded for any particular good which was in excess of the money estimate of the marginal good, the buyer would do better to abstain from purchasing this particular good, for which he would have to pay more than its value. The same considerations which -- in estimating the value in use of a stock that may be divided up at pleasure -- lead to every good, without exception, being valued at its marginal utility, also necessitate that, in the purchase of a stock which may be greater or less according to desire, for every good without exception only the equivalent of the marginal utility shall be paid. And here we see that the laws of value which we have already explained have a direct influence on the laws of price, and that the latter could not be understood without the former.(1*) If this is once established there is little more to say. At every extension o?his purchases the buyer will calculate his maximum. If we were to add together the calculations of all buyers we should obtain the quantities of goods which might be placed against every conceivable price. Where goods are held for high figures only small quantities will be sold, and that to the most "capable" buyers for the satisfaction of their most urgent demand. Where prices are low larger quantities will be sold, partly to the richest buyers to meet their less urgent demand, partly to others who are less "capable." But, at a fixed price, only a fixed amount will be demanded and may be sold. If now sellers, on their side, come to market with a fixed quantity of goods which must be entirely got rid of, they will find the price already determined. It is that price at which just this amount is demanded.
Here again we have the same determinant facts; -- the amount of supply already owned, the degree of want or desire; and the purchasing power of the buyers. The two latter have, however, the peculiarity that what decides is not simply the money equivalent of the marginal purchaser, or the marginal class of purchasers, but the money equivalent of the marginal purchaser, or class of purchasers, for the marginal good or goods.
