Cancel public exportable certificate

I understand your concern about the charges for the exportable wildcard certificates you created. Unfortunately, once an exportable public certificate has been issued, the charges apply and cannot be reversed. As you noted, AWS charges $149 per wildcard name upon issuance of an exportable public certificate.

If you no longer need these certificates, you have two options:

1. Delete the certificates: Since you're not using them, you should delete them rather than keeping them active. This won't refund the initial issuance cost, but it will prevent any future renewal charges. You can delete certificates through the ACM console by selecting the certificate and choosing "Delete."

2. Do not revoke them: Revoking is different from deleting and is only applicable for certificates that have been previously exported. Revocation is permanent and global, affecting all instances of the certificate. If you haven't exported or used the certificates, deletion is the appropriate action.

It's important to note that the charges apply at the time of issuance, regardless of whether you use the certificates or not. For future reference, non-exportable public certificates are available at no additional cost if you only need certificates for use with AWS services.
Sources
Revoke an AWS Certificate Manager public certificate - AWS Certificate Manager
AWS Certificate Manager Pricing | Certificate Management | Amazon Web Services
Delete certificates managed by AWS Certificate Manager - AWS Certificate Manager

with so much AI around, it would be great to analyze customers profile and know how much are they willing to spend, or provide some tool not to incur in excessive costs by setting a REAL limit (not just a warn of it).

But that would be only beneficial for the customers, not for AWS. That's a shame.

even more, you can't add this type of product to the section Billing and Cost Management > Pricing Calculator > Saved estimates. How convenient for AWS.