Check keyword search volume and CPC(cost per click)

[Schlocky]

This is the best free keyword search engine I have found so far:

http://www.googspy.com/

For keywords it lists cost/click, clicks/day, cost/day, advertisers, search results and search volume.

For domain names it lists the ten best paid keywords for the last six months as well as ad budget, ad position, traffic value, paid vs organic clicks. It also gives a graph of advertising budget going back at least five years if data is available.