South Park Stick of Truth because I happened to be in Target where they had a buy 2 get 1 free sale, was picking up some Wii U stuff and spied that on the shelf. Damn thing never goes on steam sales, thankfully it had a Steam redeemable key inside so I made out pretty well on the deal and marathoned through what turned out to be a fantastic game to boot. I suppose technically you could count the physical box Pillars of Eternity, but that was from KS and I've not opened it since I got the Steam key anyway, plus it wasn't bought from retail so I think it goes against the spirit of OP's question.