well price depends on two concepts : demand and offer. before the event, pandora boxes were really expensive, I couldn't tell you exactly it always depend, but i saw some around 70 mil and more. But now because of the event, the demand will go down and the offer will go up, which will greatly lower the prices. What I suggest you to do: keep it somewhere safe in your storage and wait let's say 1 year? haha it will be worth a lot just like santa set and gdf on old servers before magic pop update. (Ive been playing since august 2006 so Ive seen more than one event :) )