There are so many bad SEO techniques but this one has to be up there with the worst of them. Buying links of any kind doesn’t just cost a pretty packet, it’ll cost your site it’s ranking too as Google is now wise to people purchasing links.
Link farms are being shut down left, right and centre and people that are associated with link farms, much like spam, are finding their site is slipping down the rankings. This technique is labelled as black hat SEO, a term used within the industry to describe techniques which are sometimes illegal, immoral and punished by search engines.
Rather than wasting money and time buying links, you’d be better off investing the time in generating unique and original content and getting it in front of the right pair of eyes.