I got slapped with an unexpectedly big bill for my Azure website, and the support team is actually very good and pointed me to a tool that warns you if you are getting charged, i.e. have any apps active in the cloud.

It’s a tool called Greybox (http://greybox.codeplex.com/) created by a guy called Mike (http://mvwood.com/blog/azure-greybox-1-0/)
It runs in the Windows taskbar as a grey box and turns blue to warn you, and has a small footprint.

Azure support even has a small jingle for it. Something like:

When it’s gray, it’s okay
When it’s blue, a bill is due


Hope it helps you from cancelling your flight to Hawaii because of an Azure bill. Thanks to Mike