There is almost nothing more affordable than a Redmi 9A when purchasing a smartphone. The Xiaomi smartphone with MiUI 12 is already available for significantly less than 100 Euros (~$118). Find out in our review of the Redmi smartphone whether the low price also requires too many compromises.
https://www.notebookcheck.net/Xiaomi-Redmi-9A-Smartphone-Review-99-Euro-smartphone-with-long-battery-life-and-real-dual-SIM.503911.0.html