If you're able to set up a service that risks a high bill, but cannot set up something that turns an email into some other action (anything from a text message

If you're able to set up a service that risks a high bill, but cannot set up something that turns an email into some other action (anything from a text message to automatically shutting down your service), I don't think the limitations of AWS are the problem... (Having said that, AWS could really do a lot better with it's notification targets than just email.)