In I Know Why the Caged Bird Sings, Marguerite assists customers who buy goods at her grandmother's general store. The store is the hub of her family life in Stamps, and she describes it as her "favorite place to be." She discovers a "simple kind of adventure" in accurately measuring ladles of "flour, mash, meal, sugar or corn" prior to weighing them on the scale for customers.

This process turns into a sort of game or test for Marguerite. Depending on what the scale reads, she receives two types of responses. When she's precise with her estimations, the customers compliment her by saying:

"Sister Henderson sure got some smart grandchildrens."

When the scale shows that her measurements are short, the customers chide her:

"Put some more in that sack, child. Don't you try to make your profit offa me."

If Marguerite is off in her judgment, she imposes penalties upon herself by restricting access to her favorite treats, namely Hershey's Kisses and canned pineapple rings.