Aren ' t half lives in chemistry notPhysics ? I don ' t really remember but I ' m pretty sure it wouldn ' t be a physics textbook . <| sep |> A vassal that big would also be very rebellious , especially since the LD changes . It would very likely lead to a sort of decolonization war , which could be an interesting way of handling it . <| sep |> It ' s more about the cutoff point where something becomes expensive enough that you wouldn ' t like to buy it anymore . If you set the burger to $ 3 , both will buy it . If you set it to $ 5 , only B will because A thinks that ' s too expensive he doesn ' t like burgers much and does like to save money . It ' s better to sell two $ 3 burgers than one $ 5 burger , so if you have only these two potential customers you will sell them for $ 3 . On the other hand , if your town has plenty of people who would buy a $ 5 burger not unlikely , then you can just charge $ 5 and wait until someone else comes along who will buy one . Then you have sold two $ 5 burgers and made more money . But then , if you ' re selling the $ 5 burgers and someone opens up down the street selling very similar burgers at a lower price , you might lose your customers because they would seek out the better deal . The example is abstract but the point is that prices vary because of people ' s views , choices , income , etc . and can be dragged up or down based on what potential customers are around . From other comments I ' m guessing this is arguing against a bit of a strawman though .