I have a california-imported 240z, is was a fairly good condition z, but ugly as hell... Think it might went for arond 1000$, but it cost in total around 5000$ when I had it in my garage.
So if you add shippingcost and taxes, US-import isnt that cheap, but usually there is a lot less rust.
The z is alot more rare and exclusive over here, so I guess its more fun owning one aswell. In Norway there is just about 100 240's, and not half of them are driveable......