Still got my 2 KN7000s and wouldn't part with them for all the tea in China !! In my opinion, still the best sounding keyboard with a really user friendly operating system - especially when you want to create your own backing styles. The SD Card system and the USB computer interface make the Floppy disc mostly redundant.
KN7000s appear on eBay fairly regularly here in UK and are usually priced between £400 and £1000 ( US$524 and US$1310) depending on condition and accessories included in the sale.
Like other opinions in this thread, I think that the one you refer to is way overpriced in view of the damage... who knows what other internal damage it has sustained....
If you can find a decent KN7000 Larry, go for it - I'm sure you won't regret it.
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Willum
After silence, that which comes nearest to expressing the inexpressible is Music.
Aldous Huxley
( especially when the music is played on a KN7000....)