Arduino is a wonderful platform to rely on to build robots and learn coding. The Adeept AWR-A WiFi Robot Car for Arduino comes with everything you need to learn about robots. It has line tracking, obstacle avoidance and multiple working modes.
You will be able to control your robot car from a PC or Android app. The kit ships with acrylic plates, an ESP8266 WiFi module, 4 gear motors, 4 wheels, and everything you need to get started. You can get one of these for under $50.