• For the data goes into EC2, is Free
• Transfer data inside same AZ is free
• Transfer data from one AZ to another through Private IP: cost $0.01
• Transfer data from one AZ to another through Public Ip / Eöastic IP: cost double
• Transfer data from one Region to another Region doulbe $0.02

Summary:

• Prefer private IP over public IP for saving costs and better network performance
• Using same AZ for amximum saving (at the cost of high avaiablility)

• If you need to fetch 100 MB data from DB, and you only need 50 KB query result
  • Transfer 100 MB over network to your Corproate data center is very expensive
  • Better way is deploy EC2 inside Cloud, only transfer 50 KB data to your data center
  • Direct Connect location that are co-located in the same AWS Region result in lower cost for egress network

• Using CloudFront for better performance and cost saving

• EC2 in Private subnet transfer data to S3
  • Using NAT Gateway -> Internet Gateway -> Public Internet -> S3: cost lot more than
  • Using VPC Endpoint to S3 Bucket