In my experience its the same as most campag parts, condition is essential.
If it is in ok condition with no cassette/skewer then as little as £50, if it is great condition with all the bits then upwards of £130.
I am not sure of NOS, name your price really.
(Im only talking about Shamals here)
My Brother has a Front Shamal on his bike, I doubt he will let that one go!
The fact that you got one for free is great!
Mike