These look pretty cheap for what you get, and if one of my little apps actually got popular enough to fall outside of the free range, I'd gladly pay for it
Free quota to get started: 500MB storage and enough CPU and bandwidth for
about 5 million pageviews per month
$0.10 - $0.12 per CPU core-hour
$0.15 - $0.18 per GB-month of storage
$0.11 - $0.13 per GB outgoing bandwidth
$0.09 - $0.11 per GB incoming bandwidth
Google I/O started this morning, unhappy I am not there...