What is a marshall 30th anniversary blue half stack worth?

: : ballpark figure for a 6100 head and matching 1960a cab in mint condition?

: In Australian dollars, I have seen full stacks advertised for $4,000 but they get offered $3,000 - $3,500, depending on condition. I am in the market at the moment for a 30th Anniversary full stack.

I was hoping for a little of the same kind of input because I'm trying to sell a 30th anniversary blue combo w/matching 1-12" extension cabinet.
However I saw a couple on e-bay for sale and you might go there to monitor their bids.
Another point to consider too is that the 25th anniversary models are fairly collectable, and yet their a lot easier to find than 30th's, one reason being, in my opinion, that people don't want to get rid of their 30th's. They're a better amp, which I say with benefit of having owned both.