I find it interesting that you bring up CloudFront, because they are also very expensive. As far as I can tell, because there are so many people of there who have a mental aversion to talking to another human and negotiating, they can charge an insane premium on an "engh" service.

Regardless, if picking up the phone and negotiating with a CDN, someone whose opinion of you is totally irrelevant and where the worst-case outcome is "we won't do business with you", how are you going to handle support on your own product, or court investors of your company?