The concept of the public good is any good or service that every member of the community and society can also be used at the same time meet their needs. It is important to note that no one can be excluded from the consumption of public goods, and to have it available to all users on equal terms. On the other hand there is a private good that represents all the best in order to satisfy personal needs, and its most important characteristics are exclusivity and incompatibility. Exclusivity is a characteristic that occurs when a person is not willing to pay for the use of certain private property, but is out of it and turned off. Specifically for this characteristic is that it can not be applied to public goods. Incompatibility is a characteristic that represents the relationship of entities offering and searching for a good and occurs by direct encounter in the market. The main features are made manifest good principle Nonexclusivity and compatibility. Non-exclusivity exists when a person allows the consumption of a particular public good regardless of whether it is paid for it or not. Compatibility means the principle that characterizes the use of public goods. Public goods can be divided into clean, common, toll and meritorious public goods. For pure public goods characterized by the principles of Non-exclusivity and compatibility, the toll good; exclusivity and compatibility, while for the common good characteristic principle of Non-exclusivity and incompatibility. Public goods, it is also possible to share with respect to the object; land well, water well, maritime and air well.