From the selling side of the market, monopoly exemplifies a price maker. As the only seller in the market, a monopoly firm has the ability to control the price. Firms operating under oligopoly and monopolistic competition are also price makers, although to a lesser degree, depending on their relative market control.

From the buying side of the market, monopsony exemplifies a price maker. As the only buyer in the market, a monopsony firm is able to control the price. Firms operating under oligopsony and monopsonistic competition are price makers, but also to a lesser degree.

While a price maker is able to control the price, it does not have COMPLETE control over the market. A buyer or seller cannot set ANY price for ANY quantity. Price makers on the selling side of the market (monopoly, oligopoly, and monopolistic competition) are constrained by the demand side. A monopoly seller, for example, is constrained by the demand curve it faces. It can establish EITHER the price OR the quantity, but not both. If the monopoly seller establishes a particular price, then buyers decide the quantity that they are willing and able to purchase as reflected by the demand curve. If the monopoly seller establishes a particular quantity, then buyers decide the price that they are willing and able to pay.

Alternatively, price makers on the buying side of the market (monopsony, oligopsony, and monopsonistic competition) are constrained by the supply side. A monopsony buyer, for example, is constrained by the supply curve. It too can establish EITHER the price OR the quantity, but not both. If the monopsony buyer establishes a particular price, then sellers decide the quantity that they are willing and able to offer for sale as reflected by the supply curve. If the monopsony buyer establishes a particular quantity, then sellers decide the price that they are willing and able to accept.