All AWS Support plans include an unlimited number of account and billing support cases, with no long-term contracts.
Support billing calculations are performed on a per-account basis for all plans. Enterprise Support plan customers have the option to include multiple enabled accounts in an aggregated monthly billing calculation.
Monthly charges for the Developer, Business, and Enterprise Support plans are based on each month's AWS usage charges, subject to a monthly minimum.
As your AWS charges grow, you earn volume discounts on your AWS Support costs.
Purchasing Support for Reserved Resources
When you prepay for compute needs with Reserved Instances and Nodes in services such as Amazon Elastic Compute Cloud (Amazon EC2), Amazon Relational Database Service (Amazon RDS), Amazon Redshift, Amazon ElastiCache or others and are enrolled in a paid AWS Support plan, the one-time (upfront) charges for the prepaid resources are included in the calculation of your AWS Support charges in the month you purchase the resources. In addition, any hourly usage charges for reserved resources are included in the calculation of your AWS Support charges each month.
If you have existing reserved resources when you sign up for a Support plan, the one-time (upfront) charges for the reserved resources, prorated over the term of the reservation, are included in the price calculation for the first month of AWS Support. For example, if you purchase a three year Reserved Instance on January 1 and sign up for the Business Support plan on October 1 of the same year, 75% of the upfront fee you paid in January is included in the calculation of Support costs for October.