Are there any adwords tools that can tell you the best keywords (low CPC) by analyzing the site? Checking keyword density maybe?
Google has a tool that will tell you the keywords you have on a page. https://adwords.google.com/select/KeywordToolExternal Once you get your list of keywords, you can plug those into Google AdWords account sign up to get CPC.
Go Through this url write keyword on the box there and select Keyword Search Volume in the field Choose data to display. Anyhow it comes as a default there. Through that you can compare the advertiser competition and the search too.