Paid Link is one of the Black Hat SEO techniques which is not recommended to do. With the help of Paid Back-links, your website's rank may lose its ranking on search engine and get penalized by search engine.
If you are receiving the backlink from genuine websites which is similar to your website niche, then its good else ignore it because it will cause your website ranking.
You have to use the White Hat technique for link building.You have make back link on genuine websites. Content is incredibly important if you want to build the types of link that make a difference.