SEO keyword research tool for hackers

They're ballpark accurate for a few searches I have intimate knowledge of, though that comes with the proviso that there is no one price in AdWords.

There are many, many things which could account for you getting very low CPCs. One is that the content network != the search network, and the search network prices are generally much, much higher because they demonstrate commercial intent. Another is that you may have been subject to "smart pricing" -- Google basically has unlimited discretion to lower payouts to you on the theory that your traffic quality is not compelling.

These bid estimates are to have your ad show next to google.com search results. That's an entirely different ad auction than what happens to show up in your adsense account.

For real word keywords we actually bid on - it's way off by a factor of 3-5X.