Jack explains that his parents aren't rich, even though he goes to private school. Jack's dad is a teacher and Jack's mom is a social worker. They sold their car when Jamie started kindergarten at Beecher Prep, and they live in an apartment in a rough neighborhood in town. Jack listens to his parents talk about going without air conditioning or working two jobs. One day after Thanksgiving, Jack hangs out with Julian, Henry, and Miles at recess. Julian, whose family is wealthy, complains about having to go to Paris for Christmas. Jack begins to tell the boys about Lightning, but Miles cuts in and talks about his new state of the art, very expensive sled.
Though it remains little more than an undercurrent, the novel begins to attribute some of Julian's meanness to his wealth and privilege here—it's clear that he hasn't considered that for someone like Jack, going to Paris would be a once-in-a-lifetime opportunity. When Miles cuts Jack off to talk about his own financial fortune, it also shows that financial power can translate to social power. The boys surely know they're far wealthier than Jack, and they use that information to make him feel small.
Julian throws out that Skeleton Hill is lame, and won't listen when Jack insists a kid broke their neck there. Julian says it's an Indian burial ground, and Miles mentions that he left his old sled there and a hobo apparently took it. Julian offers to have his dad drive them all to a golf course with steep hills, but Jack hurries away. He doesn't want them to know that he's the "hobo" who took Miles's sled.
For Jack, the realization that he took Miles' cast-off sled is something that drives home for him that he doesn't want to be friends with these people. Miles' use of "hobo" is horribly classist and suggests that someone who might find joy in his old things isn't worth consideration as a full person.