Well I'm speaking theoretically because I haven't reached that point with any of my sites. Of course you should have a budget alert in AWS first of all. But th

Well I'm speaking theoretically because I haven't reached that point with any of my sites. Of course you should have a budget alert in AWS first of all. But theoretically there is no such thing as a free lunch, and bandwidth costs money. Even cache hits in cloudfront generate bandwidth. A cache can't magically transfer text to your clients, it's still using transfer cost outgoing from cloudfront cache servers.