Where is irony shown in this story?

Another great irony is that the mother finally has the money she perceives to desperately need, yet continues to be unfulfilled because she doesn't have luck in any sense of the word; she has no idea how to continue to generate money, and she has lost her young son because of her greed, indifference, and selfishness.  Earlier in the story, she says that luck is more important than money.  Therefore, even the loss of her son doesn't bring what is most important to her.