Yes we can't yet escape needing the correct OS to compile the code into binaries (Linux for Android, macOS for iOS) but technically one could start producing Android apps using just a cheap Raspberry Pi.
It goes to show that lack of finances does not inhibit one from being able to be creative and tap into a massive mobile ecosystem. These apps can scale according to screen size.
Yes there are excellent dedicated IDE's for Android app development, but with something like Python, you learn a skill which you can basically compile for any platform, using the same code.
freeCodeCamp has a good 5-hour tutorial on YouTube showing how an app is built from scratch using Python with Kivy.
See How To Write Android Apps In Python? - AskPython
Want to build Android Apps in Python? More than 3 billion devices in this world run on android. That makes it one of the most or probably the most important