For OpsWorks Stacks on Amazon EC2
There is no additional charge for OpsWorks Stacks. You pay for AWS resources (e.g. EC2 instances, EBS volumes, Elastic IP addresses) created using OpsWorks Stacks in the same manner as if you created them manually. You only pay for what you use, as you use it; there are no minimum fees and no upfront commitments.
For OpsWorks Stacks On-Premises
The pricing for each on-premises server on which you install the OpsWorks Stacks agent is $0.02 per hour. There are no minimum fees and no upfront commitments.