Purchasing backlinks?

I'm in the planning stages of starting a blog and am currently working through SEO strategies. Is it the general consensus that websites like sirlinksalot that claim to backlink to your blog on a very authoritative site are worth the money, or even legitimate? I plan on doing my SEO naturally and don't plan on using many paid services, but if driving traffic to my blog to one day be able to monetize it is the goal, would purchasing one of these services every now and then be worth it? Thanks!