For AAA titles, GTAV PC (...and, funnily enough, GTAV on PS3/consoles.) Being on PC though, I didn't actually pay "full price" - it was heavily discounted for me, even on pre-order (think I payed £16 on GMG).
I would have most likely bought MGS also, but I won a bunch of keys through a NVIDIA competition (which also included Arkham Knight, Dying Light, and The Witcher 3: Wild Hunt (I actually bought this beforehand, but I'm a cheapskate and used a VPN to buy through GOG Ukraine w/ season pass for £25

I guess it's technically full price in Ukraine though...)
Coming to think of it, it's too easy to not buy game, even brand new ones/pre-orders, with some sort of discount from their RRP. (e.g. I could go pre-order Fallout 4 right now for £25 or so, even though it's something like £50 on Steam...)
So all in all it was technically GTA5 on PS3, no discounts at all. Just bought off-shelf in store.