Hi,
I recently bought a set of rays, with only 3k miles on the rubber, unmarked, they cost me £990.
They have gone for less, but if you are in the local area of someone who wants a set (as was the case with the chap who sold me mine) you should be looking at maybe up to and over a grand.
Bare in mind these are a £1k option, andif you want to buy them new from Nissan, they quote £1k per wheel.
If these are the 06 alloys you are talking about, then you may be looking at even more than £1k, as they will be rare as hens teeth. And certainly attractive for those with pre 06 cars and standad wheels.