Billing error RDS Free Tier

Hi,

Yes, Amazon RDS is included on the AWS Free Tier, and allows to deploy the following services at not cost, during 12 months starting with the date on which you create your AWS account.

• 750 hours of Amazon RDS Single-AZ db.t2.micro, db.t3.micro, and db.t4g.micro Instances usage running MySQL, MariaDB, PostgreSQL databases each month. If running more than one instance, usage is aggregated across instance classes.
• 750 hours of Amazon RDS Single-AZ db.t2.micro Instance usage running SQL Server (running SQL Server Express Edition) each month.
• 20 GB of General Purpose SSD (gp2) storage per month.
• 20 GB of backup storage for your automated database backups and any user-initiated DB Snapshots.

I recommend that you take a look at the following Knowledge Center article, which describes step by step how to launch an Amazon RDS database instance that's covered by the AWS Free Tier.

Finally, note that last week AWS experienced an pricing issue where the Amazon RDS free-tier resources were being metered even when the usage did not exceed the free-tier limit. The issue has been resolved, but If you meet previously described requirements, I would recommend opening a support case via the console.