5. Tool: WordTracker
Good for: Finding popular, low-cost keywords for PPC campaigns, finding longer tail search terms and synonyms for SEO
URL: http://freekeywords.wordtracker.com
WordTracker is the doyenne of keyword research tools. While it is primarily a subscription service, you can use the free version to generate lists of keywords restricted to 100 phrases. The full version combines the extensive search term database with useful tools for mining the data, but the free version is a great starting point and an ideal try-before-you-buy solution for skeptics. The trial allows you to find keywords that include your specified search term, so it’s a useful resource if your PPC budget is being used too quickly by expensive terms.