[shoo]

You could get a physical computer to use as a server, and deploy your app onto it. This will have bounded costs, will require a fair bit of your time, will not teach you how to deploy to a PaaS, but may help you build more intuition and experience.

Get a cheap second hand machine to use as a server - 2 cpu cores and 2gb ram should suffice. Install debian onto it. Set it up so you can administer it remotely over ssh. Learn how to install and start your app as a service using systemd - get that working manually. Write yourself a list of all the steps you took to install your app. Format the disk, reinstall debian, see if you can follow your steps to get your app working again. Learn ansible, rewrite your manual install and deploy steps as an ansible playbook that can be executed over ssh. Format the disk, reinstall Debian, see if you can execute your ansible playbook to install your app without any manual steps. Get another second hand machine, install debian on it as well, set it up so it can also be administered by ansible. Now see if you can deploy your app to both machines at the same time, with your one playbook.

Congratulations, now you're deploying like it's 2012!