I wouldn't buy a used HD-Z1U. You don't know what the camera has gone through -- especially if the heads are bad, the lens is scratched up, the inside of the camera is full of sand, dirt, grime, etc. If I were you, I'd buy a new one at a credible place like b & h. It's a little bit more money but at least you won't wonder if it breaks, what you will do... at least for one year (warranty).
http://www.bhphotovideo.com/bnh/controller...oughType=search