It's not just egress in case of NAT - they charge you 4.5c per processed GB which means in both directions. This trips a lot of people up.

I ran into a SaaS company recently that had a guide for how to setup a white-label domain using route 53 and Cloudfront for one of their services. The SaaS company charges for service bandwidth usage, and they host their infrastructure on AWS, so if you opt to follow their guide they get a fat margin bump in the form of avoiding an egress charge and you get to be double-charged for bandwidth. You've gotta love it.