The Keywords Everywhere chrome extension until just recently was a free keyword research tool that allows you to find useful google keyword search volume and cost per click data on multiple websites.
The price is pay as you go, no monthly subscriptions. 100,000 credits for 10 bucks which believe me, for most users will be more than enough.
Keywords Everywhere will save you plenty of time that we waste trying to find data from various websites and AdWords Keyword Planner.
Keywords Everywhere lets you find long-tail phrases with their accurate search volume, CPC and competition data in all of the following:
Learn more about: Top 3 Keyword Research Tools