No, you're right. I use cloud front and you have to pay for the day at to go from S3 to cloud front servers where it gets cached. Then the costs are $0.14/gb in the cheapest region.
If your cache gets deleted or expired, you'll have to pay to move the data (at s3 rates) to the CDN again when someone requests it.
If your cache gets deleted or expired, you'll have to pay to move the data (at s3 rates) to the CDN again when someone requests it.