Hi runner50,
There is a website that lists average prices for used instruments. The KN6000 is listed at $1883. I have no idea how authoritative the website or quotes are. Here is the URL if you want to check it. Scroll down and click on "Technics Music":
http://www.prepal.com/manufacturers.htm For price comparison purposes, you could check e-bay to see if any KN6000 instruments are up for auction.
I scouted around here in the UK and bought a KN7000 for £900 ($1620). I know that doesn't help you when you live in New York. I subscribe to music magazines that contain classified ads. I see the latest issue has a KN6000 for sale at £895 ($1616), a KN7000 at £1100 ($1980) and a KN5000 at £450 ($810). I offer this information for what its worth to help you form an idea of the value of the KN6000 available to you.
Best Wishes,
Chuck