As the number of websites grow everyday, it is becoming increasingly difficult for a new site to attain good rankings on search engines. Since major search engines factor link popularity heavily into their ranking algorithms, building relevant links to your site is perhaps the single most important component of search engine optimization.
For a new site with no or few inbound links, buying text links on more established related sites could provide a boost to your link popularity. But this strategy could prove prohibitively expensive, especially in a highly competitive market where you'd have to buy lots of links to catch up with the competition.