The free version of WordPress.com does not allow affiliate links, as I understand. This is why I never recommend free hosts – the rules can wipe your site out in a flash. You need to check with them on what the pay version allows. I prefer to pay for my hosting, as then there are no rules about using affiliate links. There may still be rules about other things, especially on shared hosting, regarding the use of resources. You always need to understand the limits of your hosting. I’m using A2 Hosting right now and like them. Obviously, that’s an affiliate link.

If you’re doing something that might be considered gaming the search engines, you’re overdoing your SEO. Search engines hate that. Ease off. I don’t know which techniques you were using to advise beyond that, but I can say that overdoing your SEO can do harm in the long run, even if your results look good at first.