Amazon S3 charges you US$ 0.023 per GB/month stored, US$ 0.004 per 10,000 requests to your files, and US$ 0.09 per GB transferred. However, as we are considering the CloudFront usage, transfer costs will be charged by CloudFront prices and will not be considered in S3 billing.
If our website occupies less than 1 GB of static files and has an average per page of 2 MB and 20 files, we can serve 100,000 page views for less than US$ 20. Considering CloudFront, S3 costs will go down to US$ 0.82 while you need to pay for CloudFront usage in another section. Real costs would be even lower because CloudFront caches files and it would not need to make 2,000,000 file requests to S3, but let's skip this detail to reduce the complexity of this estimation.
On a side note, the cost would be much higher if you had to provision machines to handle this number of page views to a static website with the same availability and scalability.