Keyword Popularity is a very useful tool to determine the competition on each keyword. The harder the competition the more expensive its cost. For webmaster or someone who want to promote his site, of course, he should try to find the less competition keywords.
This keyword popularity tool will reveal the Advertiser's Competition and Search Volume. If the Advertiser Competition is very high than the related keywords would be very very expensive.
Try to find The Low Advertiser Competition but high Search Volume. It would be the best result for your budget.
This Tool is completely FREE and made by Adwords Google. Good for your website management.