Highest GA won by price on steam.

SEGA Hit Collection - can't see the price sadly, as it's no longer avaiable on steam, but it was 300 or 400$ full price ;)

The Evil Within Bundle (80P)

Some games that's 10P

Crusader Kings II 40€

Arma 3 60€
Unfortunately it was Alfa and expired after a few months... :(

RPG Maker VXace

9.99 lol

Football Manager 2015 (50p)
Orc Must Die 2 Complete edition (25)

I have been so very fortunate, winning Scribblenauts, Sonic Generations, The Talos Principle, and Shadow of Mordor.

Talos is really a beautiful and interesting puzzle game, and I've not had time to start the others yet, as I've been busy with the Batman games.

It doesn't take an expensive game to make me happy, though -- I was really happy when I won Rooms: The Main Building, for instance, and winning Ori and the Blind Forest would make me just as happy as any $50 game ^__^

Most expensive I won was warhammer space marine collection <3

Total War: Rome II (60$)