Whew, it's got "something fishy" written all over it.
Email the seller and ask:
- Will the "link" be for new or refurb product?
- About how much were the shipping costs for his?
- How long did the shipping take for his?
- Is it being shipped from outside of the US?
- If so, what kind of customs fees should you expect?
- If it's an outside the US company and there are issues, who would "resolve" them?
I've never bought something like this, but why wouldn't he just buy 10 of them for $150 and sell them for $500?? I have been looking into buying a system that's only available in Japan and the customs charges can be hefty, and there's not returns for any reason

.
My guess is this is "shady" at best, and scam is more likely.
Good luck and let us know what happens.