Yea,
He should have started bidding at $30 to get people invested, he has low quantity feedback, it's one of the oldest unit Kinesis made (circa 1995?), clearly shows signs of age, it's AT-style.
I sold my almost flawless Essential (used 2 months) for $90, (a little on the cheap side). It works on Mac with an adapter.
His is a $70-$80 keyboard relatively speaking, but people will pay more since a new one is $250+.