How many smartphones do consumers want to buy: affected by price of the smartphones, affected by other factors, including prices of other goods. Perfectly competitive market: a market with: many buyers and sellers, all firms selling identical products, no barriers to new firms entering the market. Reservation price - below the price he will pay for it and below is where he will buy it. The existence of many varieties of consumers with different reservation prices/ valuations for a product or service, can be depicted in a demand system. Suppose these valuations for smartphones exist for certain people in the economy: Consider unit intervals in making a demand graph. Demand schedule: a table that shows the relationship between the price of a product and the quantity of the product demanded. Quantity demanded: the amount of a good or service that a consumer is willing and able to purchase at a given price.