Spending limits are far more complicated than they might seem since these services are designed to be billed by usage and many accrue charges even in a steady state.
What exactly is supposed to happen when the billing limit is hit? Delete everything? That's the only way to actually stop billing completely and I'm not sure who would actually want that.
No service that I know of deletes everything even when there are billing issues. No public access is nearly equivalent from the end user's perspective, and usually there is a grace period before everything is deleted. All in all it is an interesting conflict of interest on the cloud provider's part.
http://stackoverflow.com/questions/7021506/is-there-a-way-to...
There is no way to set a budget for AWS.
http://stackoverflow.com/questions/27616776/how-do-i-set-a-c...
there is no a feature that allows you to configure a limited budget on GCE. This feature is certainly available for GAE
https://feedback.azure.com/forums/170030-signup-and-billing/...
Azure: it's possible for certain subscriptions, but not for pay-as-you-go. Sounds like there are political motives at work, not technical ones.