The narrator notes that the reader is certainly curious why anyone would even go to Camp Green Lake. They explain that Camp Green Lake is a camp for "bad boys," and the people there believe that if bad boys dig holes every day, they'll turn into good boys. Most boys there weren't given a choice about whether or not to go, but Stanley Yelnats was. He chooses Camp Green Lake over jail because his family is poor and he's never been to camp.
Stanley's reasoning for choosing Camp Green Lake over jail illustrates one way that his family's financial situation hurts him: camp under any circumstances seems preferable to jail, but this is probably incorrect reasoning, given what readers know about this camp.