Hello,
I would say around 15-17 Euros, perhaps a little more for a better exemplary (up to 25 Euros).
It si not very hard to find
IMO (here in France!), maybe loki have another point of view.
If you have found it at 30 Euros, it is probably a bit high, but without shipping, it is not a bad deal.
There is a current auction for that box
here.