Purchased this brand new from the Stanford Bookstore for $50. It's in excellent condition and still has the screen protector on it. I no longer need it and am hoping to get rid of it for $5. You can pick it up from Oak Creek Apartments.

Here's a link to the item on Amazon:
http://www.amazon.com/InterWrite-Personal-Response-System-Student/dp/B000QFMHKU