"The Body," the novella on which the film Stand By Me was based, is the story of four boys who hear of a body in the woods and take a trip to find it. Although they encounter others during the story, notably a few teens once the body is located, most of the action involves the relationships between the boys. Gordie, Chris, Teddy, and Vern talk to each other, support each other, and have conflict over both trivial and weighty matters.
Most of the prejudice in this book has to do with how the characters interact with each other, the ways they make fun of each other, and the ways they evaluate their status in society. The narrator is telling the story in first-person narrative years later and notes that all three of his friends died relatively young—a way of illustrating just how poor they were and how their lives were rarely free of violence. They lived in poverty, survived alcoholism and domestic violence, and had few economic opportunities.
These truths are revealed in dialogue in which the boys (who are 12–13 years of age) creatively mock each other for their inadequacies. Ultimately, they accept each other but are well aware of their reputations and those of their families. They are protective but realistic. They point out each other's differences.
This story doesn't explore prejudice so much as it reveals themes of status, especially status based on age (the teens almost wreck their trip), education (Chris is the victim of prejudice by his teachers), and implicitly, money.
Chris's father is an alcoholic and a criminal and he is treated like trash by his teachers even though he is intelligent. Teddy's father, suffering from PTSD, abused him as a child, leaving him with scars due to burns. Vern's family is relatively functional, but not in the upper strata of society. Teddy, with his physical scars and hearing aids, is made fun of for his disability. Vern is serious, but the other boys pity him because they believe his brother stole his change jar but don't have the heart to tell him. Chris comes from a family of criminals, but he's still respected for his smarts.
These characters are living in rough conditions and mock each other for their differences, but they also don't look down on each other because they all come from a small, poverty-stricken town. Being poor isn't anything to be ashamed of, and what prejudice occurs in the book has to do with how they are seen as outcasts of various sorts by others, including their teachers, parents, and siblings.