Economic Goods and Free Goods

우리가 물을 돈 주고 사먹듯.
수요 공급 곡선이 만나게 되면 경제재 (economic goods)가 된다.

http://en.wikipedia.org/wiki/Free_good


Free goods are what is needed by the society and is available without limits. The free good is a term used in economics to describe a good that is not scarce. A free good is available in as great a quantity as desired with zero opportunity cost to society.
A good that is made available at zero price is not necessarily a free good. For example, a shop might give away its stock in its promotion, but producing these goods would still have required the use of scarce resources, so this would not be a free good in an economic sense.

There are two main types of free goods:

• Resources that are jointly produced. Here the free good is produced as a by-product of something more valuable. Waste products from factories and homes, such as discarded packaging, are often free goods (see also dumpster diving).
• Ideas and works that are reproducible at zero cost, or almost zero cost. For example, if someone invents a new device, many people could copy this invention, with no danger of this "resource" running out. Other examples include computer programs and web pages.