I really wish you could just designate a group of resources as unimportant, set a billing limit, and let Amazon nuke everything / delete your files / whatever, if you go over the limit. Everytime I try to learn cloud infrastructure stuff I'm terrified of the literally infinite bill that might show up from a typo a month down the line.
Whilst this might sound funny, we were surprised to see it as a common use-cases with users putting https://github.com/infracost/infracost in their CI/CD pipelines to act as safety net. Currently it only works for Terraform users, but we plan to add other infra-as-code tools in the future. We're also discussing how we can do this for people who don't use infra-as-code in https://github.com/infracost/infracost/issues/840 but it's not clear what the workflow could look like for them. Perhaps having separate AWS accounts with a budget alert that emails you to run https://github.com/rebuy-de/aws-nuke is a work-around just now.
(I'm co-founder of Infracost)