Here is another micro:bit robot kit that serves as a good starting point in robotics. The Kitronik :MOVE Mini MK2 Buggy Kit is a 2-wheel robot with autonomous operation. It can be controlled using a second microbit or via a Bluetooth application. The Kitronik :MOVE mini is powered by two continuous rotation servo motors. It has 5 x RGB addressable LEDs.
This robot kit is available for under $30 at this time.