A website’s ranking is based on the analysis of those websites that link back. This link-based analysis is a very good way to measure a website’s value and can help greatly improve the quality of web search. To get a good ranking on Google the quality of links is the most important aspect followed by the quantity.
There are numerous websites one can buy links from to get them to link to your website. Some webmasters and SEO use this method of buying and or selling links regardless of their quality in order to increase popularity on the Internet. However, search engines do not support paid links. Google even has an official form for webmasters to report paid links.