Amazon EC2 Auto Scaling is an AWS service that can help users reduce the number of Amazon EC2 instances that run when application usage is low. Amazon EC2 Auto Scaling allows users to create scaling policies that automatically adjust the number of EC2 instances based on the demand or a schedule. EC2 Instance Savings Plans, Spot Instances, and Reserved Instances are instance purchasing options that can help users save money on EC2 usage, but they do not automatically scale the number of instances according to the application usage .