Here’s a great how to for simple bot “The following article will show you how to build a simple robot, called “The Beetle Robot”. It’s great for beginners and easy to do. Most of the components can be bought for much cheaper at Digi-Key, Jameco, or similar. At Solarbotics you can find the dual AA battery holder and the Mabuchi motor. You can find these components at any good electronic store.” Thanks William! Link.
HOW TO – Build a Beetle Robot