that of the final
unit of any other article that could have been had for the same money.
The auctioning, however, would cause different barrels of apples to
sell at different prices, whereas there is something in the working of
competition which causes all of them to sell at the same price. It is
necessary to see, first, how the price of the "final" one is adjusted
and, secondly, how that fixes the price of all the others.

_The Law of Diminishing Utility._--We revert here to one of those
general laws of economics that we have already stated and see it
acting under the conditions of distinctly social life. Goods of a
given kind have less and less utility, per unit, the more the user has
of them. If you offer him apples in increased quantity, he will value
the first part of the supply highly, but will attach less value to the
later parts. When the desire for this fruit is fairly well satisfied,
he will find other articles of more importance. At the price of two
dollars a barrel it is just worth his while to buy a final barrel of
them. That quantity, as added to his winter's supply, will give him
two dollars' worth of benefit. This means that it will do him as much
good as anything else which he can get for the same amount of money.

_The Equalization of Final Utilities._--Two dollars spent in adding to
his previous stock of other things will do the man in the illustration
the same amount of good that he can get from a final barrel of apples,
and no more. In the case of goods which are all alike and of which
consumers are always glad to use an additional amount, prices tend to
adjust themselves in such a way that a final unit of any one which the
consumer buys with a dollar is worth just as much to him as a final
unit of any other article he buys with that amount. The last dollar
paid for apples is as remunerative, in the way of pleasure and benefit
secured, as is the last dollar used to improve his wardrobe, to add
something to his stock of furniture, to buy tickets to the theater,
etc. Apples have, as it were, to compete with clothing, furniture, and
amusements for the consumer's favor, and if the vender charges more
for them than do the venders of other things having the same power to
give pleasure, some of the apples will remain unsold; for though
customers will always give as much as they would have to pay for other
things of equal final utility, they will not give more.

_The Prices of All Increments of Supply Equ