Amazon Web Services (AWS) Lambda is a compute service that executes arbitrary Python code in response to developer-defined AWS events, such as inbound API calls or file uploads to AWS' Simple Storage Service (S3).
Lambda is often used as a "serverless" compute architecture, which allows developers to upload their Python code instead of spinning and configuring servers, deploying their code and scaling based on traffic.
Zappa is a serverless framework for deploying Python web applications. It's a really slick project and used even by internal AWS developers for their own application deployments. Be sure to read the Zappa blog as well for walkthroughs and new feature announcements.
First Steps with AWS Lambda, Zappa, Flask and Python 3 shows how to use Zappa to deploy applications built with Flask and Python 3.
Deploying a serverless flask app to AWS lambda using Zappa provides a screen capture of one developer deploying their application to Lambda.
The AWS Lambda tag on the official AWS blog contains all the related first-party tutorials
Serverless Cost Calculator estimates the amount that AWS would charge based on Lambda exeuctions, average execution time and memory needed per execution.