Which AWS service is always free of charge for users?

AWS Identity and Access Management (IAM) is a service that allows users to manage access to AWS resources and services. It enables users to create and manage users, groups, roles, and policies that control who can do what in AWS. IAM is always free of charge for users, as there is no additional cost for using IAM with any AWS service1. Amazon S3 is a storage service that provides scalable, durable, and secure object storage. Amazon S3 has a free tier that offers 5 GB of storage, 20,000 GET requests, and 2,000 PUT requests per month for one year. However, users are charged for any additional usage beyond the free tier limits2. Amazon Aurora is a relational database service that is compatible with MySQL and PostgreSQL. Amazon Aurora has a free tier that offers 750 hours of Aurora Single-AZ db.t2.small database usage and 20 GB of storage per month for one year. However, users are charged for any additional usage beyond the free tier limits3. Amazon EC2 is a compute service that provides resizable virtual servers. Amazon EC2 has a free tier that offers 750 hours of Linux and Windows t2.micro instances per month for one year. However, users are charged for any additional usage beyond the free tier limits4.