Avoid Link Buying
 

It seems that Google�s algorithm is more sophisticated at detecting paid links, so you should avoid this if possible. On the other hand, Bing seems to be pretty far behind in this regard. Yes, if they detect a purchased oink, they will give you no credit for it. But the real question is how well are they able to detect them in the first place? Probably better to play it safe and avoid.

Buying links and traffic are now termed as black hat technique. Sometime back I bought 100 backlinks for $55 and it worked well but now they pulled those backlinks but my ranking is still the same :D. I think my links are stronger than those links I purchased. But still some guys unaware of this, buying links from several sources and nothing happens to them.

Link buying is totally unethical and anyone must not do this.

Link buying is come effected in penguin update and not suggested as White hat to build back-links for websites .

Buying links is definitely unethical and google knows which links are paid and which ones are not.