Sounds hard huh? Impossible for the common reader. Think again, Robot Building for Beginners by David Cook offers a simple guide inside the electronics and robotics world. Offering a step-by-step tutorial to Sandwich, a simple line following robot costing a mere $20 in parts. Or you can even buy a printed circuit board to make things easier( that will set u back $12). For those who want more, you can always try building a custom one as did [greg] from DIY Live. His line following robot post, includes the technical know-how for the more experinced reader who is not afraid of soldering irons.