there was a kid who made 200k in diablo 3 from botting when real auction house was still up.
the only investment was $50 for the game and his friend who coded the bot script for $50.
I`d say he came up big.
That game was certainly a gold mine for a few months after it came out, although botting isn't exactly legal. Can't think of a single other game where could make money as easily as botting in early D3.