The law of supply and demand is one of the first things you learn in life. Look at little kids playing with a toy. If there are two kids and one toy then they both want the same toy. This is true when you grow up to and a problem the United States is facing right now. Due to the pandemic and supply chains, there are many people going after few goods. This causes people to pay and buy more of the same goods. When people see something as scarce they are also likely to see it as more valuable. Sales people use this as a tool because a deal will go away or since there is only a certain amount of something it is exclusive.