Here is a free keyword tool that works!

Targeted keywords lead to much better results.

 Internet users who use four-word searches are more likely to purchase goods or services than those using fewer words

The keywords that first come to your mind will not be the best keywords for search engine optimization.

Take the time to find the perfect keywords for your website and you'll save a lot of time and money.

Keywords for comparing products in detail are best because these people want to buy.

    Use this process to get to Long Tail keywords by clicking on each kw in results to get further suggestions for keywords that contain that term.

This site explains this very well. http://www.keywordindex.com/KeywordIndex-White-Paper.pdf They also have some great SEO software but it's like expensiveeee ouch.