How do I earn money paid surveys?

Can you earn money answering surveys?

Many websites advertise affiliations for paid opinion surveys with the promise of monetary compensation, most of the time a few dollars, for those who answer these surveys.
However, many people believe that being noted in many surveys companies paid or unpaid can earn much money, which is not guaranteed.
Case that public opinion surveys, paid or unpaid, are a form of research, either on a product-cars, computers, food-or service-use of the Internet, airlines, travel, and who orders a work of this nature would like to know more about their customers or users, actual or potential.
However, the person seeking a fee for answering a survey, perhaps out of necessity to earn money, supposed to send you surveys on all kinds of items frequently, which is rarely the case.
The client of the pollsters put their money, and pay for good information. But he, for example if you produce cars, only interested in the views of those who can buy their brand and type of car, and not to anyone willing to answer a survey.
Therefore, the pollsters selected specific people according to the profile of the survey, which reduces the margin of chances of being selected to answer a survey in exchange for money for anyone.
This is understandable, as noted, considering that he handles the survey would like to take your money invested, and that opinion polls are research tools for certain targets, such as trade.
In some cases, you can have a little luck and answer surveys which pay very well, but regular attendance is by no means guaranteed.