When buyers and sellers interact how markets work. Perfect competition many sellers and lots of choice. Perfect competition: a market characterized by a large number of sellers. All sellers offer more- or-less the same product, for more-or-less the same price, and buyers have lots of choice. The key element is that you, as the consumer, feel that you have a great deal of choice as to from whom you purchase what you need. All sellers are said be small : in this case, small means that no producer enjoys a large market share. Market share: the percentage of an individual firm"s sales relative to the total sales within a given market: market share can be measure either in value terms or in volume terms. There are products/services which are available from only a small number of large suppliers maybe 3 or 4: consumers can attempt to shop around, but the choices available are limited.