There is no better way to learn coding and robotics than building and programming your own. GoodBoy is a 3D printed robotic dog that you can power with Arduino. You are going to need an Adafruit Powerboost 1000c, HC-SR04 Sensors, 9g servos, a 18650 Li-ion Battery, and a few other simple components.
This robot can be programmed using the Arduino IDE. You will need a 3D printer with a print bed of at least 210x210mm. More information is available here.