Spyfu is a brilliant tool for competitor research and both PPC and SEO insights due to the huge database of information that it possesses. SpyFu allows you to see every place your competitor has shown up on Google, including all of the keywords they have bought and the ad variations they have used. See adverts, sources and keywords for over 300 million sites in a concise and smoothly designed interface. You can run a few sample queries to see limited data provided by this tool. It also has a slick interface with plenty of important at-a-glance information easily available.
Pricing for this tool starts at $79 per month.