Absolute requirements - the first level - are abstract in relation to concrete potrebitelny costs, express the potential consumer force of society. Needs for food, the dwelling, spiritual development exist throughout all history of mankind and are incentive of production.
Classification of the market can be carried out and on ability of goods to satisfy requirements of certain groups of consumers: the market of men's, women's clothing, a commodity market for amateur photographers, tourists, hunters, etc. Feature of research of such commodity markets is the accounting of interrelations of various forms and means of satisfaction of a certain requirement.
The valid requirements — the second level — have character and reflect needs for real subjects which society has or can have in foreseeable prospect. They always have the material contents realized in concrete of production of goods and are considered as the real force of society.
The market, sales of products — is part of the market (cumulative, regional) within which sale (wholesale realization and retail sales of the goods made by this enterprise, association, is carried out. The sales market is formed and develops within a certain commodity market.
Market researches are required if the producer of goods wants to concerning the markets in which he can realize the production, and the factors influencing these markets. In other words, producers and, first of all, marketing services of many enterprises are interested in a sales market, production.