How much would a set of Azuma's lighted Sankara Stones set me back?

I was hunting around for lighted Sankara Stones, but not too happy with the crap on the bay...
So I was curious about the Azuma stones I have seen around.
If I locate them... How do I know they are a fair value?
How much did they sell in a set of three originally? And did they hold that value, or do you think they went up because they were limited in the run?

Thanks