Today we are announcing Savings Plans, a new flexible pricing model that allows customers to save up to 72% on Amazon EC2 and AWS Fargate in exchange for making a commitment to a consistent amount of compute usage (e.g. $10/hour) for a 1 or 3 year term. With a Savings Plan, usage up to the commitment will be charged at the discounted Savings Plan rates and any usage beyond the commitment will be charged at regular On Demand rates. Savings Plans offer significant savings over On Demand, just like Reserved Instances, but automatically reduce customers’ bills on compute usage across any AWS region, even as usage changes. This provides customers the flexibility to use the compute option that best suits their needs and continue to save money, all without having to perform exchanges or modifications.
from Recent Announcements https://aws.amazon.com/about-aws/whats-new/2019/11/introducing-savings-plans/