The thing I really like about Clover is it uses Raspberry Pi as a companion computer as well as ROS. Their code is open source on GitHub as well. It definitely supports Python and allows you to interface with many different aspects of the system. More details here:
In full disclosure it may seem that I’m biased towards Clover and that’s because I’ve spent much more time with it than PlutoX. It may not fit your “very cheap” requirement. What price point are you looking at?
The Tello Edu is around £130 so it will need to be under £50. The Drona Avation 1.2 Pluto nano full kit is £64 but is C++ and looking at the reviews and support looks abit hit and miss.
Maybe we could create something for developing countries ourselves