Most fun you had for the lowest amount of money ?

League of Legends, oh wait, I spend 200$ on that game

Prolly Quake 3 (+Mods). I also put 800 hours into kf, a game I won on steamgifts :>

If we're talking F2P (which I feel is cheating and shouldn't be part of the discussion,) then Tribes Ascend.

As for games I have paid for, the cheapest game that I bought that I absolutely loved was S.T.A.L.K.E.R. Shadow of Chernobyl. The first holiday sale Steam had, they had the game on sale for $1.99 and figured I'd pick it up since it was so cheap not really knowing much about it. It has quickly become one of my top 5 favorite single player franchises ever.

If we're talking F2P (which I feel is cheating and shouldn't be part of the discussion,) then Tribes Ascend.

As for games I have paid for, the cheapest game that I bought that I absolutely loved was S.T.A.L.K.E.R. Shadow of Chernobyl. The first holiday sale Steam had, they had the game on sale for $1.99 and figured I'd pick it up since it was so cheap not really knowing much about it. It has quickly become one of my top 5 favorite single player franchises ever.

Probably Tribes 2 or Counter Strike 1.6, 5+ years of fun.

Unreal Tournament. 3000+ hours and counting. But I downloaded it for free lol

team fortress 2

Garry's Mod - $2.50 during winter sale.

Saints Row: The Third from the Humble THQ Bundle.

I went out for a walk. It cost me nothing.

Binding of Isaac and the Humble Indie Bundle 5.

Throwing a penny at a wall

A rental car with full insurance and a rally course. That memory is forever.

Skyrim. Won it here :3

All this for no investment

The games were fun :D

The Binding of Isaac

The Binding of Isaac - 300+ hours
If we speak about f2p then Dota2 I guess (though I still can't master it, i like to play it).
Also like Undefined's Arkandian game series.

MU Online (in a private server)

Flipping a penny to see if it will hand on lincolns face

my girlfriend

TF2, 74 cents for upgrading to premium, 400 hrs and still rolling

Ragnarok Online.
Too many hours, too many memories.

The Binding of Isaac (1$ at HIB7) with 118 hrs played.

What about the world's oldest First Person Shooter?

Call of Duty Classics / United Offensive - Call of Duty 5? :D