[rmc]

In aws, you can set up billing alerts, so they will email you if you go over X per month. It's a good idea to set that up, so at least you'll be alerted as soon as possible if you get hacked.

[NDizzle]

This is how you handle it. Billing alarms at the highest priority. I expect mine to fire off around the 20th of each month. I expect the second alarm to never fire.

[banku_brougham]

Hacked account => billing alarms get turned off. So you won't find out.

[rmc]

Yes, it's not foolproof, but you might get hacked by someone who forgets. It's another lawer of protection.