The price of a Windows Azure extra small compute instance will be reduced by 20 percent beginning October 1. You can also use extra small compute hours to power small instances at a ratio of three extra small compute hours per one hour of small compute.
Additionally, current Introductory Special offer customers and customers who sign up for this offer prior to October 1 will receive both 750 extra small compute hours and 750 small compute hours for the months of August and September to ensure maximum value and flexibility in advance of this enhanced offer.
For details, see the Windows Azure team blog post Announcing Simplified Data Transfer Billing Meters and Swappable Compute Instances.
To determine the resources you receive with the various instances, see Windows Azure Compute.
Bruce D. Kyle
ISV Architect Evangelist | Microsoft Corporation