7.75 CHF per piece for 3 units
Canon EB
Eye cup
Canon EB
Eye cup
Yes, the eyecup fits the 80D. I bought it for the 60D, so it's the same for both models.
It fits my Mark III. I don't know if the Mark II has the same viewfinder, but you might be able to compare the item number in the camera manual. All accessories are listed there.