I thought I couldn't use my registrar's DNS unless I wanted it to redirect to the weird URL for the s3 bucket. But maybe I've got it all wrong and just took someone's S3 static site build instructions too literally 5 yrs ago.
https://docs.aws.amazon.com/AmazonS3/latest/dev/VirtualHosti...
You can also use cloudfront to do SSL if you need it.
Note: If you're really only need to host a static website and want SSL for free, Github static hosting will give you all that for free. https://pages.github.com/