Today I've got a bill with unexpected $200 (I stopped but not destroyed container). So I suggest you to make an option that send customer daily bill. And it would be better if this option will be enabled by default.
Tomorrow we will be announcing a new billing feature which will send you an email notice whenever your usage for the month hits a threshold that you set.
This way you can always stay informed about your usage and not get surprised at the end of the month.