Google has finally introduced a billing system for its Google App Engine. Before today, Google App Engine developers faced quotas on bandwidth, CPU, and API calls. It's about time - Google has been promising this since May 2008. Not surprisingly, the limits for free usage will be lowered but you can still serve up to 5MIL pages/month for free. It's a sign that Google is making a business out of Web Services and not treating it as a hobby. Google is less flexible, less robust, and offers less than Amazon (no offline processing, for instance) but with similar pricing. Both charge $0.15/GB storage and $0.10/GB inbound traffic. For outbound traffic, Google is cheaper ($0.12/GB vs $0.17/GB).  I see no advantage for using Google over Amazon.