If i had a PR1 and build backlinks on a PR0 but the keywords are related to my site, would it affect my ranking?
Every link helps in the long run. Short term that link will do nothing but if you have thousands of links then they all will help. You may get traffic through this link as an added bonus.
PR0 is help but not much because Pr0 dofollow website still have some PR point, just the PR point is not enough for it to get PR1. besides, PR0 quality website will help much if you look for long term
hey r u addicted on having a PR? well well try submitting your site to social bookmarking sites so that it will be recognized and just keep on adding new contents so that when PR update comes Hope youll get a PR
PR0 links don't help all thta much, they aren't truly PR 0, that is just how they are displayed, they could be calculated to have .3PR for instance via google's algorithm.
Links from related content mean more than the PR of the page now days. Focus on getting links from related pages. If you can get a related page with good PR of course that's better...but don't go chasing unrelated links from high PR pages.
If its related to your website. why not try to link on them? Besides, who knows, maybe it got PR on next PR update.
PR0 will help either way. A link has value no matter what. If you can get a PR0 link and it doesn't take much time to get it then get it.