Have you considered the possibility that he's racked up a huge debt to someone? Or he's friends with a shopkeeper? Or he owes a huge debt to his friend, the shopkeeper?
You could also go the Charlie And the Chocolate Factory route: the kid's super-poor, but his entire community is (for some reason) riding their hopes and dreams on him and contributing their pittances towards his uber-deck.
Unless everyone's been lying to me and the next bunch of episodes are The Great Divide II, The Great Divide III, Return to the Great Divide, and Bride of the Great Divide, in which case I hate you all and I'm never touching Avatar again.