Not too much... Around $150
Here is a touch screen kit:
http://www.digitalww.com/images/Tkit2.JPG
It consists of a Touch Panel, USB Touch Controller, USB cable and a controller to panel extension cable.
Connect everything together and attach the touch panel to the LCD panel. That is it. A lot of the people here have this kit.
Armen
Quote: Originally Posted by williamn333
digtalww, I would like to get one for a 15" LCD. How much more would it run than the 12.1? BTW, how exactly do they work? Are they as accurate as a normal touchscreen? Anyone in here have one of these that can tell me how they like them?