A monopoly is where one person or business is the only one in a region to offer a specific item or service. The four types of monopolies are complementary monopolies, bilateral monopolies, government granted monopolies and historical monopolies. Government granted monopolies are when the government grants exclusive rights to a person or business. A bilateral monopoly is when there is a single seller and a single buyer. A complementary monopoly is when there is consent between more than one entity to obtain the goods or services needed.