• Monopoly.

A monopoly is defined as a market that has only one firm, meaning that the market is served by only one firm. The types of goods produced in this market are those goods that are unique and have no close substitutes.

• Oligopoly.

An oligopoly market structure is a market that is served by a few large firms. These firms produce goods that are homogeneous products (such as gasoline) or differentiated products (such as airline services).

• Pure competition.

Under pure competition, there is an infinite number of firms that serve the market. The firms produce goods that are identical or homogeneous and perfect substitutes. For example, in the grocery market, there are many sellers who sell the same groceries.

• Monopolistic competition.

A monopolistic competitive market contains blends the characteristics of perfect competition and monopoly markets. In this market, there is a large number of firms, just like in perfect competition, but the firms in this market do not produce identical products. Their products are slightly differentiated though they are close substitutes. For example, bathing soaps.