Redis is a type of database. It is a key value store, meaning that data you access in it follows a simple pattern where every value in it is accessible via a simple key. While you can use it for lots of things, typically it is not used as the primary database for a website. Redis is often used as a cache or session storage, so in a hypothetical ecommerce website you would maybe use it like that.
AWS is a series of infrastructure offerings from Amazon. These include hosting, managed databases, domain names, and much more. A self-hosted ecommerce shop might run on AWS infrastructure.
From your questions, I'd direct you to Shopify, Rackspace or Woocommerce - they have a lot of stuff set up for you already. It's an ecommerce shop in a box.