What do you think about link buying?

1. Buy links individually instead of in packages.
2. Deal directly with site owners instead of with 3rd party companies.
3. Don't buy links from sites that openly state (on their site or elsewhere) that they sell them.
4. Buy links from sites that are relevant to your own site.
5. Buy in-content links instead of links in the sidebar or footer.
6. Buy links on individual pages instead of site-wide links.
7. Keep the percentage of paid links below 10% of the total number of links your site has.

Link buying is one of the black hat techniques,nothing but buying links from others.If your link profile is nothing but a  paid link, that is very risky.I dont prefer this kind of technique.Link buying can only be effective if you are good in choosing the right site. But it's a waste of money if you don't know how to investigate the site first. It will drag you financially low.

Buying or selling links that pass PageRank. This includes exchanging money for links, or posts that contain links; exchanging goods or services for links; or sending someone a "free" product in exchange for them writing about it and including a link.