Diablo 3 - best price you have seen so far.

50% off is the lowest I've ever seen

On PS3/PS4 there is currently a discount :-)
If you need PC version, you should look to any local store.

They will never be less than 50% off. If you're looking to buy them, go for it when you see that kind of price tag.

50 % sounds really good, it means I can pick up D3 + ROS for around 20 EUR.

i haven't even seen Diablo 3 on steam..

On pc it never goes below 50% because Blizzard hates us and wants all our shiny pennies D:.

Tip when buying Blizzard games in Europe: Go price hunting for physical copies.
I got my RoS for 20 euros in store. (edit: should add that at the time I got it, Battle.net digital store was charging 35 euros for the base version)
Should have gotten the base game as physical copy as well at the time, that would've saved me a bunch of cash too.

I got it cheap as hell. I paid something like 23 euros for retail copies of both back in august :) You could try some of the shadier sites like g2a and such, the base game was 9E or something last time i saw it mentioned and ROS was 19-20E, however i'v heard people complaining about blizzard games bought from such sites getting removed from their accounts so it's kinda risky. From the Bnet store you will never see it cheaper than 50% and they do such deals every 2 months or so from what i'v seen.

As it was mentioned, physical copy is your best bet, but with the recent price reduction, indeed you can hunt the 50% off on online stores. With Blizzcon coming soon (November 6) you should watch the Blizzard store.