The market is known as “a group of buyers and sellers of a particular good or service” (Mankiw, 2012, p. 66). Everyone interacts with each other in a market in everyday life. In general, markets can be classified into four types: perfect competition, monopoly, monopolistic competition and oligopoly. The first type of competitive market is perfect competition. Perfect competition has three characteristics. First, there must be “many buyers and sellers in the market, [firms that] can freely enter or exit the market and each [firm] selling an identical product, so each buyer and each seller are price takers” (Mankiw, 2012). , p.280). For example, in the egg market there are many sellers and buyers. Sellers therefore have no market power to influence the selling price and must therefore follow the market price. Furthermore, the firm's decisions in perfectly competitive markets can be classified into short-term decisions and long-term decisions. The short run is defined as a period of time during which each firm has a given plant size and the number of firms in the industry is fixed; while the long run is defined as a period of time during which the quantities of all inputs can vary. In the short term, the company can decide whether it wants to continue producing or close the industry, as well as how much to produce if it decides to produce. In the long run, companies may choose to enter or exit the industry, resulting in an increase or decrease in their plant size. The advantage of a perfectly competitive market is that it is easy to enter or exit the industry and consumers can buy an identical product at a fair price; while the downside is that sellers cannot increase the selling price as they wish. Profit-maximizing production is the middle of the paper. Consumers can plan and balance their spending. Indeed, the oligopolistic market has stable prices (Sonkushre, 2012). An oligopolistic market scammer faces the problem of cheating. According to Arnold (2008), some oligopolistic firms collude to reduce the quantity of products in order to increase their demand for products. Another disadvantage of the oligopolistic market is the high barrier to entry and exit from the market (Arnold, 2008). This creates difficulties for new companies wishing to enter the market. In conclusion, there are four main types of market structure in the economy: perfect competition, monopoly, oligopoly and monopoly. They differ in the number of sellers and buyers, short- and long-term profits, and barriers to entry. No market structure is better than another because they all have their advantages and disadvantages. Some may benefit consumers in ways that others cannot.