AWS billing after trial ended

Hello.

You can search for active resources in your AWS account by following the steps "Confirm you have terminated all active resources" in the document below.
I think it's a good idea to check if there are any resources that charge a fee among the search results.
If you haven't used AWS that much, there may not be many resources in the search results, so I think it's easy to check the documentation and determine whether the resources will incur costs.
https://repost.aws/knowledge-center/check-for-active-resources

Hi there, You can submit a ticket to support team and ask them to check which services are under using on your AWS account. With that information you will know which services should be suspended. https://support.console.aws.amazon.com/support/home

Another best practice is using AWS Resource Explorer to efficiently search for and discover your resources across AWS Regions and accounts. But you must enable it before using AWS services. Check the document here: https://aws.amazon.com/resourceexplorer/