How to stop Relational Database Service?

Hello.

Even if an RDS instance is stopped, it will start again in 7 days, so I recommend deleting it if you are not using it.
There is also an option to create a snapshot when deleting, but if you do not need a backup, disable that option and delete it.
https://repost.aws/knowledge-center/delete-terminate-rds

To stop all Amazon RDS related charges for your account, you'll need to take a few steps:

1. Log in to the AWS Management Console and navigate to the RDS dashboard.

Option 1: Identify and stop all running RDS instances:

• Select each active instance
• Choose "Stop" from the "Actions" menu - This stops the RDS instances only for 7 days in a row.
• Note that stopping an instance will only stop billing for compute hours, but you'll still incur storage costs

Option 2: If you are no longer using the RDS instances you can also permanently delete them.

• Choose "Delete" from the "Actions" menu

You can also remove any remaining snapshots and automated backups if you no longer need them.

• Go to the "Snapshots" and "Automated backups" sections
• Delete any unnecessary snapshots and backups

5. Clean up associated resources:

   • Delete any unused subnet groups, parameter groups, and security groups
   • Check for and delete any active RDS Proxies
   • Verify and delete any AWS Backup plans associated with your RDS resources

6. If you're still seeing charges, use the AWS Cost Explorer to identify any remaining RDS-related resources that might be causing fees.

If you continue to see unexpected charges after following these steps, it's recommended to contact AWS Billing Support for further assistance. They can provide a detailed analysis of your account and help identify any hidden resources that might be causing ongoing charges.

By following these steps, you should be able to stop the Relational Database Service and eliminate the monthly fees you're currently experiencing.
Sources
Stopping an RDS instance

Managed Relational Database - Amazon RDS Pricing - Amazon Web Services

https://repost.aws/knowledge-center/rds-stop-seven-days