Luke must sell his automobile in order to hire a pilot and ship to fly himself and Obi-Wan. Luke doesn’t get much in return for selling his automobile though since a newer model was released and they’re not in demand anymore. This is due to the increased demand in similar but newer and perhaps improved goods, called a substitute. The improvements of the new model also change the tastes and preferences of the consumers, as they want the more improved model. Learn more about Demand/Supply and Substitutes from this clip!