The Amazon Web Services Economics Centre provides access to clear information and easy to use tools and resources that will help you to compare the cost of using Amazon Web Services (AWS) with alternative IT infrastructure.
The tools AWS have provided really help quantify the cost/benefit of cloud computing as you can model certain usage patters and determine the likely cost/benefit of each approach to meeting these infrastructure requirements.
The latest of these tools, Amazon’s EC2 Cost Comparison Calculator, is perhaps the most informative as it helps determine the annual costs of EC2 vs. co-locaton vs. on-site hardware.
It is easy to use and can be modified to reflect your specific requirements. You can download the spreadsheet here.
The AWS Simple Monthly Calculator which seems to have been around for ages includes all of the services and regions on offer but due to the fact it is geared towards a monthly estimate it is less useful for analysis purposes. That said, the customer samples are interesting, and cover the primary scenarios we would suggest using AWS for.
The point is even before you speak to a specialist I would suggest playing around with these tools.
They won’t make a decision for you but they will indicate whether or not you should be investigating AWS further.