Meet the Geekbot V2: a kit that lets you build and experiment with your own rover robot. The GeekBot Rover is powered by an Arduino-compatible microcontroller. It has a payload capacity of 2.2 lbs and comes with a 4400 mAh battery that runs for hours.
The robot can avoid obstacles. It has LED and buzzer outputs. The kit comes with chassis, mounts, wheels, buzzer, LED drivers, and everything you need to get started. It costs $149.95.