On the Magento Google Checkout Page.
“Process sales for free
Google Checkout merchants that are also AdWords advertisers will earn free credit card processing based on their use of Google AdWords, Google’s performance-based advertising program. For every $1 you spend on AdWords, you’ll be able to process $10 of sales through Checkout for free. For all other sales, you’ll be charged a low 2.0% plus $.20 per transaction.”
I think they quit doing this about a year ago, at least they started charging me for transactions fees regardless of the Adwords.
Anyone still getting free transactions with Google?