Many people will talk about linking building as the secret to SEO. This is because in the "random traffic model", the amount of traffic your site receives is a function of the inbound links to your site, and the popularity of the sites / pages linking to you.
As soon a search engine "specialists" discovered search engines using this methodology, they immediately set about exploiting the knowledge, swapping reciprocal links and setting up link farms. It is not in the interests of search engines to have results manipulated, and so the search engines set about penalising the sites they thought were deliberately breaking the rules. Most famously BMW were actually de-listed at one point and Bigmouth media have received more than one rap on the knuckles for bending the rules to far.
So link farms are a definite no-no and reciprocal links (give me a link and I will give you one) do not count anywhere near as highly as one way links.
Knowing all of this do you still think you can beat the system. Perhaps the best way to find out is to try it yourself. Link building is a slow and tedious affair. Done in the right way, it will drive traffic, and search engines will follow. The key is to set up your link building campaigns in a way that is deliberately designed to drive traffic to your site. In doing this you will not break any rules.
Be prepared for some hard work and great rewards. Alternatively if you are going to pay somebody, pay based on results, with fixed prices.