Interestingly, DynamoDB is cheaper than S3 though, compared by number of requests. DynamoDB costs $1.25 per million write request units and $0.25 per million read request units. While S3 is $5 per million PUT requests and $0.4 per million GET requests.
That's a good point, only very small data is cheaper in DynamoDB than S3. Also adding global secondary indexes tends to add cost, since writes are charged for each of them.
