Just picked up a non-functioning Casio CZ-101 on eBay for 16 pounds. It looks like the batteries have leaked everywhere and it possibly has been left out in the rain. It's appearance is very shabby and it is in need of a complete break-down and thorough clean. It will definitely need to be thoroughly tested for signs of internal damage or shorting. There might be some rust on the boards and contacts as well, but I have a close friend who is a qualified electronics engineer who will help me find the problem and fix any areas worthy of attention.
It was sold AS IS and for parts only, but it is complete and there are no cracks, no dents, no scrapes and no structural damage at all. It looks like it was left outside for a few weeks or more with it's batteries still inside and they leaked everywhere and ultimately left it in unusable condition. The metallic-blue paint finish has partly faded away with signs of acid running along it and the keys, in the grooves, buttons, etc. Though at the same time, all of the button labels, graphics and logos are in excellent condition. The LCD screen is uncracked and undamaged and all the keys themselves are straight and tight. It has it's original battery cover and there was even an RA-3 cartridge plugged in it!
But for 16 pounds from eBay, it makes a great source of spare parts for a rebuild or restoration job. I'd love to buy another and tackle the job of bringing it back to in-store quality!
At the end of the day though, I wish I got it for nothing because that's about as much as it's worth!