There is no better way to learn about robots and coding than building and programming your own. Educational kits such as this Arduino Programmable Robot Bike are also worth a look. This particular kit is designed to get you familiar with self-balancing robots. As it moves, it can maintain its balance without human intervention.
The robot runs on a 1900mAh battery, which lasts 90 minutes. It has a TB6612 motor and MPU6050 posture sensor. It comes ready to go but you can develop your own code for it.[where to get it]