Yeah, that's a bit confusing. Using Cloudfront with an S3 bucket is double billed, the first time. On a cache miss Cloudfront pulls the object from S3 and serve

Yeah, that's a bit confusing. Using Cloudfront with an S3 bucket is double billed, the first time. On a cache miss Cloudfront pulls the object from S3 and serves it to the client. S3 bills the regular data transfer out. Cloudfront then bills the regular data out to client rate. On subsequent requests, cloudfront cache hits, you're only billed by Cloudfront. Cloudfront request + byte rates are cheaper than S3 in Us-east-1, IIRC. So on popular or high ttl objects it's cheaper to serve through Cloudfront. On low ttl or low rps, like a few requests per day, it's cheaper to use standalone s3. The same origin + CDN vs CDN Hit math applies to EC2 as well. I do wish the billing was clearer in these scenarios.