I mean, do not use a lot of exact match anchor texts cause this will trigger one of the important spam algorithms (panda, or penguin, I don't remember which one).
You said you'll purchase 5 links. Well (especially if your site is new and has no/few backlinks), do not link back to your site/page with the same anchor text 5 times or, worse, with the exact match keyword 5 times. For example, assuming you want to rank for the keyword "teach puppy how to stop barking" you don't want all 5 backlinks to link back to your site with the anchor text "teach puppy how to stop barking". This will mark your site as spam 100%. Just use that anchor text only once, and make the other 4 anchor texts generic: click here, this website, this page, our blog, visit us today, more info, etc