How do subscriptions in the cloud for Red Hat Enterprise Linux work?

While Red Hat Enterprise Linux cloud services include access to the same technology as other subscriptions from Red Hat, the on-demand nature of this offering includes some key differences in the subscription model.

• Monthly Subscription: Customers who subscribe will be charged a monthly fee for access to the maintenance and support for Red Hat Enterprise Linux. This subscription provides customers with access to Red Hat Network as well as access to AMI's within the EC2 infrastructure. As long as a monthly subscription is maintained, customers will have access to the services and will be able to start and stop servers on the Amazon EC2 web service.
• Hourly use fees: Upon instantiation of one or more servers at EC2, customers will be charged on a per-compute-hour model based on the type of server (Small, Large, Extra-Large) specified when the instance was started. For every server that is started, the customer's account will be billed individually for the use of that server by the hour.
• Bandwidth fees: Charges for actual bandwidth used into and out-of the EC2 web service.
• Storage fees: While there is no charge for use of the included storage with the instances (see below), there are additional fees for the use of persistent storage at Amazon's S3 service, which is highly recommended during the beta period.
• One Subscription per Account: Amazon Web Service (AWS) user accounts are required for all users who purchase this offering. As the product is providing access to an AMI - each AWS user account will only be permitted to purchase one (1) subscription to cloud computing Red Hat Enterprise Linux. Once purchased, each account can instantiate multiple servers on EC2 and can easily scale the service to meet the needs of the business. (source)