Advice of SEO Tools for beginners: free or paid?

Learning slowly on SEO for months now. I would like to get advice on SEO tools free or paid.

Currently, I am using Google PR ranking, Alexa traffic ranking and inbound links, google analytic. So far I found they are quite helpful, particularly, if you go through the process of a website from 0/10 to 2/10 (PR), n/a to 3,000,000 (alexa traffic), comparing to the data from Google analytic, it will give me roughly idea how much traffic would be if a website ranks in these ranges.

However, I have been told PR wasn’t accurate, alexa traffic is only accurate under 100,000.

If so, any tools I can use free or paid version?

This topic has been covered in other threads.

Please Search using the vBulletin Advanced Search