You can set up alerts and triggers, up to pulling the plug automatically. Not exactly for the faint of heart.

GCP

https://cloud.google.com/billing/docs/how-to/budgets-program...

AWS

https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2...

https://aws.amazon.com/about-aws/whats-new/2020/10/announcin...