Here's some great free tools from Google, but to get the best benefit, you should have an adwords account. it doesn't need to be funded. But it does need to be active.

https://adwords.google.com/select/KeywordToolExternal

https://adwords.google.com/o/TrafficEstimator

https://ads.youtube.com/keyword_tool

If You Know Of More Free SEO Tools.. Please Post Them Here!

Thanks Biz_online I missed the traffic estimator.

Thanks Biz_online I missed the traffic estimator.

As Google appears to be completely dominating the search game, Yahoo is trying to borrow a page from Google' playbook by offering their own version of Google Analytics.

I would like to say that I have tried this tool, but I am so deeply embedded into Google's own Web Master Tools that I have not really looked deeply into Yahoo's tool kit.

But for anyone who is interested, here are the links to investigate further:

Yahoo! Web Analytics Features