Amazon has a pay-per-use pricing scheme, however the rate of GB stored and transferred can vary depending on the different storage locations.
Basic pricing for the first 50TB is around $0.02 per GB, excluding transfer cost, and assuming you’re using ‘Standard’ S3 storage. The first 100GB of egress (with exceptions*) is aggregated across all of the accounts connected services and free.
On top of basic costs, there could be charges if you’re exceeding the corresponding API operations (like GET,LIST,PUT,COPY etc).
Transfer costs also differ per region, the egress price per GB can be over 10 cents per GB if your storage is in an ‘exotic’ location such as Tokyo or Sao Paulo *except China and GovCloud