Google Checkout
Google's fast-growing checkout system offers you an alternative payment processor for credit card payments. You need only establish a Google Checkout Merchant account. While Google does not have the long history managing payments that PayPal has, they have created a strong, flexible, highly secure system. Like PayPal, there is no setup or monthly charge for this account, just a small commission on your sales. Learn more about Google Checkout here.
Choice of Payment Processors
You may enable either PayPal, Google Checkout , or both checkout options in your cart.
Merchant ID and Merchant Key
AuctionInc requires both your Google Merchant ID and Merchant Key. These can be found on the "Settings" tab of your Google Checkout account, under the "Integration" menu.On this same page, you will note that "My company will only post digitally signed carts." is checked by default. AuctionInc uses this highly secure method of integration; thus, please leave this option checked.
Also, as the screenshot below shows, you need to enter into the textbox labeled "API Callback URL" the following URL:
https://www.auctioninc.com/ipn/ipn_google.php
When you enter this URL, a set of radio boxes will appear below it. Check the one labeled "HTML: name/value pairs" as shown in the screenshot.
That's it! You may ignore the "Advanced Settings" link on this page.
Sandbox Testing
Like PayPal, Google offers the ability to set up a "sandbox" account. This account allows you to test the checkout process without creating real orders. If you have established a google sandbox account you can instruct AuctionInc to use it with this setting. Your Google Merchant ID and Key will need to be specific to your sandbox account. Important: Be sure to change your configuration back to "live" and update your Merchant ID and Key to your live account when you are done testing! 
