EC2 Service for Web Hosting a container for Game Applications
* ~ 10 cents per HOUR of CPU
* ~ 12 cents per GB of data transferred
RDS Service for Relational Database Storage
* ~ 12 cents per GB of storage
Typically; standard projects can expect to pay ~72$/month.
Several high-end gaming companies use Amazon Web Services:http://aws.amazon.com/solutions/case-studies/