Specs are quantitative aspects of the option such as the price
Pros
Pro
Easy scaling
You pay for a number of "Workers" for your web app (to handle requests), or CPU seconds for code that you run outside a web app, and you can get more workers or CPU seconds by upgrading your plan any time.
You can run a website at USERNAME.pythonanywhere.com for free, and it's good enough for a light-traffic website -- it runs 24/7. You get a free MySQL or SQLite database too.