Excellent idea. Please describe how to create an account on AWS or GCP that is not allowed to spend more than $100/mo. Since it is "a really easy fix" and "takes almost no time" it should be easy to explain, right?
That's probably enough for 99% of people, and if you're highly motivated, you could make that trigger an SNS notification that trips a circuit breaker.
While you can footgun yourself with hard limits I tend to think that learners/hobbyists should, in general, be able to access at least many services with an ironclad guarantee that they can't be billed for over a certain monthly amount or a total number.
I'm much more inclined to shrug if a startup screws themselves over with a hard spending limit than if a student screws themselves over because of a lack of one.