Freetrack works quite well with 6dof, depending on the width of view of the camera. I might get the next camera up which has a 15 degrees extra. Any cheap webcam will do, mine cost me a whopping 9£. The slightly newer logitechs are faster, better field of view and uses less CPU, and costs about 30-50£. I have the cheapest one and it works perfectly, I simply cannot fly without it.