AWS is a pay as you use service. You pay only for what you use. Pricing is an hourly rate but depending on which instances you choose, you pay by the hour or second (minimum of 60 seconds) for each instance type. Partial instance-hours consumed are billed based on instance usage. Data transferred between AWS services in different regions will be charged as Internet Data Transfer on both sides of the transfer. Usage for other Amazon Web Services is billed separately from Amazon EC2.
For EC2 pricing information, please visit the pricing section on the EC2 detail page.