Students and self-learners want to experiment with doing complicated things on AWS without getting a surprise $3,000 bill because their script didn't shut down those instances like they thought it did. They want a hard fail-safe to protect them from surprise bills. And they want a solution that's easier and more reliable than checking the AWS itemized breakdown twice a day.

I agree with that. That is why there are "Billing Alarms" in big letters on the billing page. But that wasn't the point of the reply: the person above me was complaining that there's no way to tell what services are being billed, which is bunk.

The breakdown isn't granular enough by far. ec2 is a very big bucket to go digging into for costs.