ELECFREAKS Cutebot

The ELECFREAKS Cutebot is a differential drive robot kit that is designed to accept a BBC micro:bit board (the brains). These components are sold separately for a total cost of around $60 per robot.

The micro:bit can be programmed in MicroPython or C++.

Online MicroPython Code Editor (Beta) | Legacy
Adafruit: Programming with Arduino (C++)

The micro:bit is recommended to be used with a special build of MicroPython specifically made for the micro:bit and its nRF52833.
BBC micro:bit MicroPython documentation

Here's a MicroPython library you can use to help control the Cutebots:
https://github.com/Krakenus/microbit-cutebot-micropython