The Spumoni mx Clack is currently valued at $900.
Do you have a link?
He owns the only one in existence. So he is valuing it at what he pleases. Half joke, half truth (he may very well only let it go for that amount).
I think I saw some caps go for $350 last summer in an auction, but I don't remember. I'll check on that.
Edit:
Here's a link. I can't recall higher prices than the highest Clack prices in this thread. Clack prices are a bit of a sore subject around here, though, so be aware of that. I'm simply posting this for the sake of information.