If you are feeling a bit adventurous and open-minded as you begin this venture, I would highly suggest looking into Elixir and Phoenix, especially since you are asking for "...best bang for the buck".

In fact, the 1.8.0 release for Elixir was just announced earlier today here: https://elixir-lang.org/blog/2019/01/14/elixir-v1-8-0-releas... (https://news.ycombinator.com/item?id=18903602)

What makes Phoenix great is that, not only is it blazing fast, but the framework serves as more of a web interface to your application as oppose to "taking over" your application, like with other major frameworks. Moreover, you get the full power of Erlang and OTP as well. I will have to say that some things are a little rough still, like deploying your application. This process is not as smooth as what you would experience with a Rails or Django app, but it will definitely get better over time. One of the features of Phoenix that is also really exciting is LiveView. If you have some time, definitely check out Chris McCord's 2018 keynote: https://www.youtube.com/watch?v=Z2DU0qLfPIY

There are a lot of great books and resources to explore. I listed a few below:

https://elixirforum.com/

https://elixircasts.io/

https://www.manning.com/books/elixir-in-action-second-editio... (just released)

https://pragprog.com/titles/category/elixir?f[sort_by]=pubda...

https://www.manning.com/books/phoenix-in-action

With regards to Python, I cannot give too much recommendation as I have experience in Ruby/Rails and Elixir/Phoenix primarily. However, if you really want to begin building, stick with Python, since you already have experience with that language, and look into a popular framework, like Django or Flask.