How old were you when you built your first computer?

I rebuilt an HP from the ground up, that was my first.

I spent about $1200 on my first build, but it was a gift. Most of my other components I have bought myself thus far.

13-14 I think, spent some >1000€.

First rig was Frankenstein'ing two older machines that had stopped working, thing ran pretty nicely for at least a few months before the BSOD's became more than occasional.
What I can recall of the specs. Costed nothing as it was scavenged from old parts.
Phenom x4 955
MSI AM2+ motherboard.
6GB of DDR2 800Mhz (only had a 32bit OS...)
Passive cooled Gigabyte 9600 or 8600GT.
1TB Seagate Barracuda.
Generic ???W PSU.
Generic case.

Used the above as practice for my current rig which I got 4 months later (just as the above stared dieing again). Specs are in my sig and the total cost is ~$2000 AUD.

Oh yea, and I was 14.

The first computer I ever had was an HP tower. I forgot the model name, but it had an Athlon 64 X2 3800+ with a power supply I took from a friend's old Dell, and I think 2 different brands and sizes of RAM. I put in a 8600GT, that I still have today.

I had that for a long long time until I built my first.

My first build consisted of:

Phenom II 965BE
ASUS 785 something AM2+
4GB DDR2 RAM
Radeon HD6950 2GB (still have this) reference model
Thermaltake V9 Black Edition
Ultra LSP 750W
Caviar Black 1TB and the salvaged 200GB from the HP.
I actually forgot to buy an optical drive, and luckily I was able to use the one from my old HP.

All of these parts are still in use today, but are scattered across my many builds.

Its becoming an addiction. I've got 7 or 8 builds now.

Start of 2010, I would've been thirty-three,
It cost about £450 and I still have it under my desk as my work/saviour Pc
x3 435 (unlocked and clocked to 3.5GHz
sapphire 5770 1Gb
4Gb noname ram

In contrast to my latest build last year
x4 975Be
Two Asus 6950 2 Gb DCII-H20's (watercooled and modified to not look like it )
8Gb Vengeance
and far too much Watercooling kit,
Two X20 750L reservoir/pump combo's,
Two T-Virus reservoirs
Rasa Cpu block
EK Hf Supreme copper Vga blocks
Rx240 radiator
Two EX360 radiators
One modified chiller (peltier)
Three eight channel fan controllers and 29 fans including Psu and a modified fan over the Cpu block
I lost count around £1500, but that was before the external radbox so maybe two grand? ish? **Edit, GBP, not USD**
and I like modding hehe

Done plenty of refurbs/refits since I built my first and enjoyed every minute of it, now I'm 'That Pc guy' at work and get a healthy little boost to my monthly slice,
Moto

13. I am only a few years older now, but I've learned much. At the time I spent ~$300. I had no problem with having used parts from Ebay as long as they were good value.
I am also quite proud in the fact that my parents did not aid me in any financial means in order to gain that money. (Or I could have spent so much more) Yay for online financial opportunities be it from web/graphic design, programming, moderating, "youtubeing", or even surveys (ew, I know).

Late 1998 or early 1999. It was a 450Mhz Pentium II based build to replace my almost $4000 IBM Pentium 233Mhz with MMX Windows 95 box. Ahh the good old days. I was 24 or 25.

27. (last year lol, I didn't have internet access or much money when I was a kid.) I wanted to replace my ageing Sony Vaio with a desktop PC seen as it spent most of it's time being plugged into the wall anyway so I put this together:

ASUS M4A88T-V EVO/USB3, Phenom II 1100T, Corsair A70, 8GB Corsair XMS3 DDR3 1333mhz, Sapphire 6950 2GB, SAMSUNG HD204UI, LG blu-ray, Corsair 600T Graphite, AX850.

I wanted it to be a multimedia PC to begin with but then a few weeks after building it I decided that I was getting bored with the Xbox so i decided to add the 6950. Ever since I put that card in, my Xbox hardly gets touched anymore  . It cost about £800 including a Samsung SyncMaster P2450, Windows 7 Home Premium 64 and Logitech mouse and keyboard.

Even after such a short time I've learned a lot and looking forward to building a proper gaming rig when Haswell arrives.

Any other late starters want to share their stories?

I can say I recognise your avatar hehe, my first computer was a C64, remember the old paperclip trick to reset it for cheats?
happy days lol
Moto

A Bodged together 486 and I was really young (about 10 think) It was parts from 2 broken PC's my grandad had sat in the house wasn't so much a build as a transplant. It worked though..... he sold it to his dam friend after all my hard labour!

First proper build was an AMD K6 233MHz I think I was around 13 and I had saved every penny I came across for what seemed like a lifetime to get a PC. AMD's K6 was a fraction of the price of an Intel Pentium it was my only option other than a 2nd hand 486 box! It was paired with a secondhand motherboard, secondhand RAM and a case I pulled from a skip that had this massive dent in the side...... It was awesome as it was mine, even if I had to turn it on with a screwdriver. I even put a Voodoo2 in it at one point. With that machine I discovered everything form PC gaming to early Internet porn

Lol Yeah my first computer was a C64 too, but no i didn't know about the paperclip trick or any other trick really. What did it do and how did you do it?

You loaded up the game as normal, then touched a paperclip to two contacts on the peripheral socket at the back, that reset it to the blue 'ready' screen, you then typed in whatever cheat code the magazine/mate/toilet wall had provided and when you initiated that the game came back on with the cheat/s enabled
I was about 12 and I remember feeling great about this trick hehe, guess I've always been a lawbreaker lol
@Wr6133, the earliest known example of net porn is quoted below, hopefully moderators won't ban me for showing it,

I was/am 23. I did my first build August 31 this year. For everything I spent about $1,300. I learned everything from this site. I was sick of gaming on my old laptop and couldn't be happier with my desktop.

I had Sinclair ZX80 kit for my 12th birthday
- what I wanted was a Sharp MZ-80K though.

16yrs old

2008 900$ Core 2 Duo era. 4gb ddr2 800 ram, 320gb HDD (IDE), antec 300, ep45-ud3p, HD4670.

Now 20

15 years old - my first rig was a Gateway tower with a 300W PSU, 12MB video card, 1GB of RAM, Pentium 333 MHz, and CD-ROM drive. My Samsung smart phone has more power than that PC.  

Probably 16 when I built it earlier this year (maybe 17 which is my current age).

Granted I've been acquainted with older PCs and did other computer related things in the past. This was my first complete build though. I recall using an old Pentium 200Mhz PC and loading it with Xubuntu and running Windows 95(maybe 98).

Current build is an i3-2100 with a 6850. Built modestly using a bunch of deals and coupons.

12. It was a Phenom II dual core and a 9800 gt from my first computer. (Which was older than I was.)

I was 12 when I built my first and that was 7 years ago...
I got three pc's gathered the best parts from all of them and made a doom 2 pc with a sprinkle of castle wolfenstein (barley played it!) those were the days 
I think I had 1 5200 rpm hdd that had 40gb of space
1gb ddr 400mh ram (or maybe it was 600mh oh well slow!)
single core 1.6-1.8 ghz cpu
I think my video card was a 1600 gforce 128mb ddr 750mh.. lol can't remember
and windows 98 backbones lol peace of $hi?

14 $265 July of 2012  

i3 2120
Asrock h61m DGS motherboard
4gb G.Skill Ram
Corsair 430w psu
Zalman Z11 (I want to replace)
Re used HDD from HP

badass system for under $300 I render pretty good 720p on Sony Vegas
Still saving $$ for gpu