FEAR 2: Project Origin

Steam - Complimentary

Team Fortress 2 - Gift/Guest Pass

STALKER: Shadow of Chernobyl - Steam Store

The Orange Box - Dem Classics!

Defense Grid: The Awakening
Worms Reloaded (preorder)

Team Fortress 2 Retail was the first thing I ever had on Steam. I still have the physical copy and receipt from 2009 (I think) somewhere.

I also got Portal free.

But my first ever purchase was Guns of Icarus.

Jan 16, 2010
Free
Purchase
Call of Duty: Modern Warfare 2 Retail

Let the hate begin!

Portal Bundle

Portal - Steam Store

The first one was of course, Steam (Complimentary). XD

The second entry is Humble Indie Bundle V keys. Then followed by Dota 2. \m/

Then about 4 months later, I started using Steam regularly, with my first purchase as XCOM preorder.

Dec 22, 2010, Defense Grid. It was 75% off then I think, and I love tower defense games.

6 July 2008

NVIDIA Portal: The First Slice

Super Meat Boy. Bought the ultra edition in store(!) and had to activate it on Steam.

Serious Sam HD The Second Encounter

first is ATI Half-Life 2: Deathmatch / Half-Life 2: Lost Coast Promo
but my actual first purchase was Zombie Driver (regular) :P

My steam voyage started with the CS:S, DOD:S, and Half-Life Deathmatch pack. Counter strike was pretty much all I played until I became interested in other games and began expanding my library.

Alpha protocol

Call of Duty Modern Warfare 3 - U$D 60

Mar 4, 2010 - Borderlands DLC: Dr. Ned - Purchase - $9.99

Half-Life Platinum Pack, but it says that one was free. So the next would be Empire:Total War.

May 19 2010 Portal - Complimentary (Opt In)
The first one i paid for however was The Valve Complete Pack in the winter sale 2011.

Terraria

29 Mar 2009 19,91€ Purchase Defense Grid: The Awakening, Harvest: Massive Encounter

And first games
Half-Life 2 Retail Standard Complimentary
Half-Life Platinum Pack Complimentary

I registered Steam to buy "Earthworm Jim Collection" (it was a weekend or midweek deal) as a gift to a friend, who later became my boyfriend, who now is my ex-boyfriend. So that's my 1st transaction.

Half-Life 2 Retail Collectors. (2008?)
First purchase is Garry's mod.