Regarding to backlinks, I hope you are talking about backlinks that are relevant to your web site, meaning if your web site covers Titanic, the movie of James Cameron, it is arguably helpful to your SEO if you get a link from movie related web site, or a web site/page focus on James Cameron. Depending on the intelligence of Google, which BTW we do not know, if you get a link from Cameron' own blog if he has your SEO may also benefit.
Anyway, my point is you need to make sure all of the sites / pages from which you purchased links are focused on the same genre as your site does. Otherwise you are wastering your money and time. Even if you may get some juicy from links that have nothing to do with your site, sooner or latter, Google and other search engines will find out. The reason is simple, people which click your link from those sites find your web site has nothing to do with the web site they are browsing. It is annoying to users and Google (As Google claimed they are helping people finding information)
Now, if you brought good links, the best option is to put your home page link on them. however, depending on your landing page, and the relevance between your site and other sites you got links, you may consider put it on other pages as well.
I hope I made myself clear