What is the first Store Transaction entry on your account?

It was Ys Origin, I made the steam account because of it.

Puzzle Dimension

The store record in that transaction list only goes back to 2008 regardless of if you purchased something earlier.
My actual first purchase for this account (I looked it up in my email) was 2004. The hl2 silver package that has most of valves stuff at the time.
A more accurate way to tell when you first joined steam is goto profile, then look at the part on the right under "gameplay stats" that says "member since" or your steam badges on right. The steam badge will have a number which is your "years of service". Mine is Nov 2004.
That account is one of the first 5 million to be created. I created it to avoid duplicates with my HL1 and other puchases from my other account (silly I know with hindsight).
That first steam account I created was dated september 12, 2003, with a hl 1 platinum pack cd key.
I was one of the first 15,000 users to sign up to steam on that account.
Incidentally, that was the day steam was first officially released. You had to use email addresses as your username to sign up back then.
Which makes me wonder if I signed up for the steam beta with counter strike 1.6 beta prior to that date, and maybe that date is only the earliest they record (like how the transaction records only go back so far).

Anyone else here sign up on or before steam's VERY FIRST DAY? :)

First purchase was Team Fortress 2 - In-Game Upgrade

First game purchase was an amazon purchase Nexuiz Retail

First game purchase directly from steam was Payday: The Heist & PAYDAY The Heist: Wolfpack DLC

Dec 12, 2008 - Left 4 Dead 49.99

NVIDIA Portal: The First Slice - Complimentary

I got a free Half Life 2 Deathmatch off that NVIDIA/ATI offer. they took it off recently and half life 2 deathmatch has been dead ever since. damnnn shamee.

First time Civ5 GotY went on sale.

hat simulator 2010

Free Portal is the first thing on my list, next is CS.

Aug 25, 2009
Team Fortress 2 Retail

It was cheaper to buy a physical copy at the time.

I've been on steam for 4 years and i never bought a game, lol.

Dota 2 - Single License Retail

funny mine says May 25, 2008 The Orange Box Retail, But I go a few years back further with Half Life 2 GOTY seeing as how my account just hit 7 years old on the 24th of dec. last year I'd say that 12/24/05 was my account creation. Both HL2 GOTY and Orange box are store bought i.e. from best buy not online and I still have the orginals

24 May 2008
Free
Purchase
Half-Life 2: Episode One

Terraria- Steam Store

E.Y.E.: Divine Cybermancy - Four Pack

2006 - Red Orchestra :)

November 15, 2012. Ten days after my birthday, and a bit over two months since I joined Steam. I think I only had Team Fortress 2 in my library. Anyway, I had been told of "daily deals" that occured on Steam the night before, and I was pissed that I had missed Super Meat Boy the day before. I decided to check out the daily deals from that moment on. As it turns out, a little-known game called NightSky was on sale for $2.49. It looked intriguing, I bought it, and loved it. The next day, I learned about Humble Bundles (actually, I knew about HIB for Android 4 a couple of days prior to this, but debated getting it). And so began my addiction to Steam.

And then there was the time I had invented the terlet and made cats and dogs mortal enemies. It all started when...[forcibly dragged off of forum]

ATI Bundle - got HL2 (+ CS:S) free with my graphics card (Radeon 9600SE) back in 2004, but due to the Source Engine games being delayed in release, ATI threw in Valve's collection of GoldSrc games with it as well.

First thing on my list is the humble THQ bundle November 2012. And I started steam a few years ago yet I never bought anything.

22 Aug 2007
Free
Purchase
ATI Half-Life 2: Deathmatch / Half-Life 2: Lost Coast Promo

10 Mar 2011
Free Purchase
NVIDIA Portal: The First Slice

11 Oct 2008 The Orange Box Retail

• 19 Sep 2009 Garry's Mod

Feb 14, 2009 Left 4 Dead

Hmph. That can't be right, since I've been on Steam since 2003. o.O

Half-Life 2 Retail Standard November 18 , 2004