Static Cost for AWS Services

You are correct in your assumption that AWS Transfer Family has a static cost component, but it's important to understand the full pricing structure.

AWS Transfer Family, which includes SFTP, FTPS, and FTP protocols, does indeed have a static cost element. Specifically, in the US East (Ohio) Region, enabling any of these protocols on a server endpoint costs $0.30 per hour per protocol. This is a fixed cost that you incur regardless of usage, as long as the server is running.

However, it's crucial to note that the total cost of using AWS Transfer Family is not entirely static. There are additional variable costs based on your usage:

1. Data transfer: You're charged $0.04 per gigabyte (GB) for data uploaded or downloaded over these protocols.

2. Managed workflows: If you use post-upload processing, there's a charge of $0.10 per GB processed.

3. SFTP connectors: These are charged at $0.001 per connector call and $0.40 per GB of data transfer.

4. AS2 protocol: If used, it has both a static component ($0.30 per hour per protocol) and a variable component ($0.01 per message).

So while there is indeed a static cost element for running the server, the overall cost will vary based on your usage patterns, data transfer volumes, and additional features utilized.

It's worth noting that many AWS services follow a similar model, combining both fixed and variable costs. Always refer to the specific pricing pages for each service to understand the full cost structure, as it can be complex and may vary by region.
Sources
Managed File Transfer—AWS Transfer Family Pricing – AWS
Configuring an SFTP, FTPS, or FTP server endpoint - AWS Transfer Family

Bharath - If I understand correctly, your definition of "static cost" refers to a cost that will occur as soon as you create or spin up the service without using it. correct?

As you know AWS pricing model is PAYG (Pay as you go). For some services, you'll start paying as soon as you create or configure the service e.g. FTP or EC2. Then, there will be additional charges based on your consumption. For some other services, you are not charged until you start using them such as Lambda function. In general, if the service reserve or allocate a resource for you, then there will be "static cost", such as DB or EC2 or ECS, because they are running in the background.

I hope that answers your question.