For those who don't own Vessel of Hatred, beware: That "100% off" sale in the shop is a lie.
I didn't own Vessel of Hatred. Saw this deal in the shop, basically advertising a free skin. I (A dumb idiot) figured this was Blizzard's cheeky way of securing a sale. "Buy Vessel of Hatred and we'll toss in this skin for only 1 silver!" (I realize now that it's actually advertised as '-1' silver.)
2nd screenshot shows you can't secure the deal until you actually own the expansion. After purchasing the expansion, the price tag changed to 40% off, as shown in the 3rd screenshot. Felt pretty scammed, I can't lie.
Sale before purchase of expansion
The sale after Vessel was added to my account.
Edit: Screenshots weren't showing for some reason.
Editedit: Refund secured, no worries there. Just wanted to share this as a sort of PSA. Surely a bug, doesn't seem like the kind of thing they need to do intentionally but it still felt deflating at the time. CS assured me they passed the issue on to their dev team, so hopefully it gets fixed.