1. You place the Checkout referral button on your site.
2. Someone clicks on the button, signs up as a buyer with Google Checkout using a valid U.S. credit card, and completes a purchase of at least $10 before shipping and tax through Checkout within 90 days. (The current $10 minimum purchase corresponds to our existing $10 promotion for new buyers, so this amount may change in the future.)
3. You earn $1.

It’s that simple. Please note that Checkout referrals are currently only available for U.S. publishers, and Google Checkout is currently only available for buyers with a U.S. credit card. We hope to make both Checkout and Checkout Referrals available in more countries soon.

If you’re not convinced, why not try it out yourself? It costs nothing to sign up (actually, you’ll even get a $10 bonus) and it’ll make shopping online a little easier. And remember, if you’re still figuring out how to improve the performance of your referrals, take a peek at our optimization tips for referrals..

You can get started with Checkout referral ads by visiting the AdSense Setup tab in your account. We think your users will thank you for showing them Google Checkout, and your wallet will like having some extra money for you to spend at all of those great Google Checkout stores.