Supply refers to the total amount of specific products and services that is available for customers, which is provided by the suppliers. With the goal of earning profits, the suppliers and companies are always more likely to manufacture products at a higher price. For supply, there is also a simple principle that if the price of goods is low, the supply is also low; when the price of goods is high, the supply is also high. For example, in the supermarket, when the price of milk is low means the quantity of milk supply is also low, while when the price of milk is high means the quantity of milk is high.