One of the ways to get your site higher on the search engines is buying links. Buying links has been a thing going on in the webmaster world for quite a while. It's when people buy link space on another site to gain more back links.
When buying links you have to know what you want before you buy. You are either going to go for page rank to boost your page rank or trying to gain more publicity. Of course the higher the page rank the higher the cost is going to be. But another option besides page rank is SEOmoz latest page strength tool http://www.seomoz.org/tools/page-strength.php which calculates the strength of the page by different ways besides just Google. So before buying any links I would strongly suggest checking the page strength since it gives the overall value of the site. The tool takes information from total back links, age of domain, pages indexed, Alexa rating and other sources. You don't want to buy a link just from what people say about their site, believe it or not people do lie. So it is always best to check with some tools to really see what you are buying.
Sometimes you also want to sell links on your own site. But you will probably ask yourself why you should sell links on your website. Well there is a simple answer to that and it is extra money you can earn. Plus when you have other links on your website it doesn't look that bad because it's not some big ad or anything like that. Sounds like a good deal right? But how can you determine the price of your link sales. There are plenty of tools to go by, the main one being Google Page Rank (PR). The higher page rank you have the better your website is listed in the search engines. Another great tool is the tool we mentioned before Page strength tool.