I saw one on Ebay that didn't shift for £500. Sterling Grey. No idea why, though when I asked the seller questions, as a genuine buyer to fit wifey's car, he came across as a bit of a knob.
Then there are others that go for around £1k.
I guess it's pot luck who happens to be looking for one.
Having a storage stand and the requisite side covers etc are good bargaining points.