When the demand is greater than the supply of goods, the price of that good will go up because there is less of it. The people who made the product need to be paid, and the people who distributed it need to be paid, and everyone else who had a hand in it needs to be paid. So if there are tons of a product, then the price will be cheaper because the company can afford it. But, if there is not a lot of a product, then the price needs to be higher because there is only a limited stock. Did I explain everything clearly? Have a nice day!