I am still frustrated with the amount of incidental complexity required whenever I want to do this. My latest attempt was to use a Digital Ocean droplet with Django pre-installed. I guess the biggest issue there was setting up something so that I could easily deploy my local version to the droplet (ended up using git/Github), and ensuring those two environments were in sync. I looked into Docker in some detail about a year ago, and I think it's the only pretty good solution for this I've come across—but there's a steep up front cost in learning/setup etc. (or so it seems).
What services and technologies do you use when you'd like to quickly build a web app which may never be more than a prototype, but may also turn into something real? A big aspect of what I'm wondering is about automatically setting something up for keeping local/production environments in sync, quickly deploying to production, and not having to mess with a bunch of server configuration things, user accounts, security, etc.