Describe how Walter, Ruth, and Mama feel about money

It helps narrator create some tension.

Explanation:

When a story is told using the third-person limited omniscient point of view it means that the narrator is not a character of the novel and he doesn't know everything related to the participants or the context.

The narrator can create tension due to the lack of information, making the reader look for answers where there might be none or some questions might remain unanswered or they will be solved as the story develops itself.