The final scene of Memento (which is actually the beginning of the story's timeline) shows Lenny drive off in a Jaguar that has a box full of money in the trunk. Presumably this money is why Dodd tries to catch Lenny later in the timeline, and also why Teddy so badly wants the keys to the Jaguar.
What happens to the money as the timeline develops? Most importantly, what is its status at the end of the timeline, after Lenny has killed Teddy (which is actually the beginning of the movie)?