In most cases, a market is characterized by a dynamic system of economic forces. The four most salient economic forces are supply, demand, competition, and government intervention. The terms buyer's market and seller's market describe different conditions of bargaining strength. We also use terms such as monopoly, oligopoly, and pure competition to reflect the competitive situation in a particular market. Finally, the extent of personal freedom and government control produces free market systems, socialistic systems, and other systems of trade and commerce.1
Again, placing these labels on markets allows the marketer to design strategies that match a particular economic situation. We know, for instance, that in a buyer's market, there is an abundance of product, prices are usually low, and customers dictate the terms of sale. US firms find that they must make tremendous strategy adjustments when they sell their products in Third World markets. The interaction of these economic factors is what creates a market.
There is always the pressure of competition as new firms enter and old ones exit. Advertising and selling pressure, price and counter price, claim and counterclaim, service and extra service are all weapons of competitive pressure that marketers use to achieve and protect market positions. Market composition is constantly changing.