There is no additional charge for AWS Elastic Beanstalk. You pay for AWS resources (e.g. EC2 instances or S3 buckets) you create to store and run your application. You only pay for what you use, as you use it; there are no minimum fees and no upfront commitments.
The costs of running a web site using Elastic Beanstalk can vary based on several factors such as the number of Amazon EC2 instances needed to handle your web site traffic, the bandwidth consumed by your application, and which database or storage options your application uses. The principal costs for a web application will typically be for the Amazon EC2 instance(s) and for the Elastic Load Balancing that distributes traffic between the instances running your application.
For more details on AWS service pricing, see the pricing section of relevant AWS service detail pages:
Amazon EC2 Pricing (includes pricing for instances, load balancing, elastic block storage, and data transfer)
Amazon S3 Pricing (includes pricing for storage and data transfer)
If you want to use an AWS database service with Elastic Beanstalk, see links below for pricing:
Amazon RDS Pricing (includes pricing for database instances, backup storage, and data transfer)
Amazon DynamoDB Pricing (include pricing for data storage, throughput capacity, and data transfer)
Amazon SimpleDB Pricing (includes pricing for storage, data processing, and data transfer)