As the story’s other protagonist, Felix Rannells exudes an air of careful integrity that provides a crucial counterbalance to Benji’s impulsiveness. A quiet, rule-abiding boy, Felix is burdened by anxiety that largely stems from his family’s precarious financial situation. His home life, which is marked by a nearly empty change jar and his mother’s extra shifts at work, has instilled in him a deep-seated caution, rendering him the moral compass of the narrative. When Benji first steals the $20, Felix’s immediate reaction is guilt and panic, and he worriedly insists, “We broke the law” (10). His persistent anguish over the consequences of this immoral choice reflects his logical and risk-averse nature. He is uncomfortable with attention and prefers to remain in the background, and this tendency is challenged by the sudden and public nature of his newfound wealth.

In Felix’s relationships, he feels a strong sense of responsibility for his mother and his older sister Georgie, and their financial struggles weigh heavily on him. Laura Friendly’s contest creates a significant internal conflict, as its strict rules prevent him from using the money to solve his family’s real-world problems. This tension is most evident in his inability to directly pay for Georgie’s wedding dress, and he is forced to come up with a creative and uncomfortable workaround.

Throughout the month, Felix evolves beyond his rigid rule-following and learns to recognize when rules need to be bent. The immense pressure of the challenge forces him to become more assertive and to take calculated risks, and his initial timidity gives way to decisive action, as when he confidently makes the half-court shot at the Celtics game and later stands up to Aidan Rozman. As his friendship with Benji grows, both boys learn to depend on each other, building a genuine bond built on mutual honesty and support. The trauma of Freebie’s accident solidifies this connection, as this crisis requires emotional resilience rather than money. By the end of the story, Felix has not abandoned his moral principles, but he has developed a more mature and flexible understanding of the world, recognizing that sometimes the greatest growth comes from stepping outside of his comfort zone.

Laura Friendly is the eccentric billionaire who sets the plot in motion, serving as a complex figure who is both antagonist and mentor. As the founder of a massive social media company, she is detached from the everyday financial realities of the boys’ lives, and to her, the contest is a grand social experiment and a source of entertainment. However, her primary motivation is to impart a moral lesson, as seen when she frames the challenge around her own childhood experience of stealing a Crunch bar and enduring a pointed punishment from her mother. This story indicates her core belief in facing the direct consequences of one’s actions. Although her contest causes the boys a certain amount of anguish, her ultimate goal is to educate them about the nature of money and its associated responsibilities. As she tells them, “A penny isn’t nothing. It can be the start of something big” (29), and this comment foreshadows her intention to teach them that even small choices can have enormous consequences.

Despite her role as a teacher, Laura’s methods are extreme and often appear cruel, and she betrays a distinct lack of empathy for the boys’ situations, especially Felix’s. When she characterizes the challenge as something “tremendously fun to watch” (32), it is clear that she is underestimating the collateral damage that her own spontaneous whim—fueled by her immense wealth—will inevitably cause for others. 

Although she maintains a certain level of emotional distance from the debacle that she puts in motion, her character is given a modicum of depth when it is revealed that she missed her father’s death because she was away on business. As she confesses to Felix, “[I]f I was granted a do-over—if I could buy a do-over—I'd be there at his side” (245). This personal failure explains her conviction that money cannot solve every problem, and her tale adds a layer of pathos to her otherwise cold demeanor. She is a static character in that her core beliefs do not change, but she does show deeper moments of understanding, as when she sets up an unlimited fund to take care of all of Freebie’s needs. In the end, she remains a powerful, enigmatic figure who uses her immense wealth to manipulate the world around her, albeit for what she perceives as a moral purpose.

Reggie Fazil, the university student whom Benji hires as the boys’ chauffeur for the month, functions as a mentor and a source of comic relief. As a philosophy major, he frequently offers academic and humorously out-of-place commentary on the boys’ chaotic adventures. However, he also strikes a more serious note when he introduces concepts like determinism to explain the chain of events following the theft of the $20, providing a more thoughtful framework for the novel’s focus on The Unpredictable Consequences of a Single Choice. Unlike the boys’ parents, Reggie is a non-judgmental adult presence; he provides practical support and a grounding perspective without imposing the same emotional weight that the boys’ family members do. His easygoing nature also allows him to navigate the boys’ extraordinary circumstances with stability and humor, and he proves to be a reliable and steadying force, most notably when he pays the initial deposit for Freebie’s emergency vet care.

Alma Miranda serves as a moral counterpoint to the world of instant gratification that Benji attempts to create with his newfound wealth. She is principled and independent, consistently refusing Benji’s offers of free food and other material goods. Her polite rejection of his attempts to buy her favor forces Benji to confront the limitations of money, and he must find ways to show his genuine goodwill to pursue a friendship with her. In one particular scene, she challenges his superficial understanding of friendship by questioning his habit of buying people’s favor, asking, “How will you know who your real friends are?” (164). In essence, Alma represents a value system based on character and sincere interaction, and she cares little for markers of wealth or social popularity. Her interest in Benji develops only after he begins to show his authentic vulnerability, and she therefore acts as a catalyst for his emotional growth by pushing him to be a better person.

Aidan Rozman is a minor antagonist who represents the superficial and opportunistic aspects of middle-school social dynamics. Invariably focused on popularity and status, he is quick to attach himself to Benji after Benji becomes a millionaire. Even so, he is equally quick to mock Benji, using the nickname “Barney” to undermine his confidence. As Aidan indulges in ever-intensifying bullying behavior, his taunts push Benji and Felix to rely on each other, inadvertently strengthening their bond.

Benji’s parents, Mr. and Mrs. Porter, embody the novel’s critique of societal and familial pressure. Their primary concern regarding the money is to ensure that it is managed properly, and they are also keenly aware of the status it represents. They are deeply invested in their son’s success, wanting him to succeed at basketball, because they consider the sport to be a family legacy. This intense focus on achievement fuels Benji’s insecurity and his desire to prove himself. Their attempts to control his spending and decisions culminate when his father uses legal channels to freeze the boys’ bank account, creating one of the story’s major conflicts. While Benji’s parents are well-intentioned, their actions reveal their fundamental failure to understand their son’s emotional needs, and their mistakes show that parental expectations can become a significant burden for children and adolescents who are still finding their way.

Felix’s mother, Karen, and his sister, Georgie, provide a grounded perspective on the realities of a precarious financial situation. Their lives are a constant negotiation of bills, work shifts, and necessities, and these worries contrast with the abstract, high-stakes game that Felix is now forced to play. The sudden wealth introduces immediate tension, for both boys mistakenly view it as a panacea for their problems, and the secrecy of Laura Friendly’s challenge causes Felix’s family to proceed on false assumptions about the family’s new financial situation. Both Georgie’s hope for a dream wedding and Karen’s decision to quit one of her jobs to pursue her education demonstrate their desperation for a better life. These desires place a heavy emotional burden on Felix, who is torn between his family’s needs and the restrictive rules of the challenge. Their situation highlights the real-world pressures that make Laura Friendly’s experiment far more than just a game.