Purely Competitive Market: In pure sense, there are no actual world markets which are purely competitive. There cannot be since purely competitive markets need: an infinite number of buyers; an unlimited number of sellers; each and every firm selling a similar product and all buyers be familiar with that; free information regarding the price charged by all sellers; and firms contain no costs of entering or exiting the market. Not one of such requirements is totally fulfilled by any real market. The purely competitive model is helpful, though, in spite of the lack of realism in its suppositions since it is relatively simple to use, and its predictions are excellent sufficient in most conditions in most markets to be helpful.