O'Conner works hard in this story to make the symbolic meaning a timeless meaning. She did not indicate a specific time period or make reference to world events. Although the setting is clearly the South, that choice is in keeping with her other works and so does not suggest a specific reference to Southern culture.
So, what is the meaning then? As the title suggests, it is symbolic of personal salvation in a world controlled by money. O'Conner shows people in the story who have a strong interest in personal, materialistic gain. Lucynell is the only one who doesn't, but she is a mute - suggesting that the pure of heart no longer have a say in this capitalistic and greedy world. The protagonist, Shiftlet, is taken over by his greed, and becomes controlled by his desire for monetary gain, although he said in the beginning that he thinks the world is too controlled by money. The story of Shiftlet is one of failure, and he is a lesson to readers. O'Conner is symbolizing the loss of morality in society, and teaching readers to step back from a life of material wealth.