AWS S3 pricing - data transfer in/out

Question

I am planning to store objects in S3 standard storage , each object could be of 100MB in size so monthly it could go upto 1TB. I will use a single region to store these objects in S3.
I want to create a mobile app to store and fetch this objects using post/get apis. And then show them in my app.
S3 uses different pricing sections, I understand storage and requests (post/get) pricing.
My question is around data transfer in/out pricing, in my case above will I be billed for data transfer in/out? if no why not?

Answer 1

Yes, you will be billed because you mobile app will connect from internet. Even connected from within AWS there are fees associated with your number of requests and data transferred (inside region or outside region).

You can use the AWS Calc to get an estimate for the cost associated: https://calculator.s3.amazonaws.com/index.html

Answer 2

All traffic FROM mobile phones to S3 or EC2 is free. All traffic TO mobile phones from S3/CloudFront is billed according to a selected region. Take a look at https://aws.amazon.com/s3/pricing/ .

Keep in mind that incoming traffic (to S3) is free only if you're NOT using S3 Transfer Acceleration.