@LeenaLinus,
Google is a major player in the online advertising industry. Every time you search Google, you'll see ads displayed along with your results. Those ads are never "mixed in" with the results - there is no "pay to play" on Google... which is one of the reasons Google became the most popular search engine in the first place. But the sponsored text-link ads above and to the right of the results generate a great deal of money for Google. These ads are known as "Google Adwords." Those who wish to advertisevia Google can learn more on Google's Adwords page and make more money.