Explain how the ending of "The Gift of the Magi" is an ironic situation (one in which actions lead to an unexpected outcome).

In the story, Della and Jim each sacrifice the thing that means the most to them in order to give a gift to the other.  Della sells her beautiful hair in order to buy Jim a platinum fob chain for his pocket watch, which is his most prized possession.  Jim sells his watch to buy Della tortoise shell combs to wear in her hair.  It is ironic that each gave up what was dearest to him/her out of love for the other, yet the sacrifice was pointless.  Della could not wear the combs Jim bought for her; Jim could not use the watch fob Della bought for him.