I also don't prefer buying links. But if the site have massive visitors then it can be effective for traffic. If google finds it then it is forbidden.
I would not recommend link-buying. Reason being that the search engines can detect that your links are coming from paid sources or link farms. They will stop ranking your website even if you discontinue the act. This will harm your site in the long run.
Avoid devious tactics to improve your ranking.
No need to buy do your quality work.