in the simplest terms the definition of demand tells us the desire or willingness of a customer to pay a certain price for a particular item she wants to buy. Suppose that the seasonal price of a pair of sneakers is 180 TL. The same sneakers cost 100 TL in the discount season. A customer therefore may prefer to buy it at the discount season, and even maybe buys two pairs instead of one pair. Therefore, demand is proportional to the price of the goods.