I don't think for me it was so much a price, as a realization that there is stuff out there that is unimaginably better then what I had.
For years I had used a pair of insanely crappy Logitech speakers (Little white ones that were so light they probably would have floated in water, and been none the worse for it).
Then I got a pair of headphones to play games, for better positional sound. They're the first ones on my signature list. Then I bought a second pair about half a year later, because the first ones were uncomfortable. The second pair were the Koss's, and when I got them I thought 'Wow! This must be what true hi-fi sounds like!' (Out of an onboard AC97).
Then this is where the actual spending comes in. I was in CompUSA and I saw a pair of Razer Barracudas, and being a complete n00b to the audiophile world, assumed that if they look cool and cost over a hundred dollars, they must be awesome. So I bought them.
Then I found out that they need a multi-channel sound card, so I bought a Creative Audigy for about 40 bucks. Shortly thereafter, my Razer headphones broke after three days of use. So I sent them back, but while they were in shipping, I needed a pair of gaming headphones. So I came here, and bought a BeyerDynamic DT770 pro. Knowing what I do now, I might have bought it in 80 ohms, but I got a 250. That was my first real headphone purchase.
After the DT770s, I became actually addicted, because I realized they were actually part of the high end (although after reading head-fi for a while I realized not the really high end). The only thing I had to power them was an old speaker amp, so I decided I needed an amp for them. I didn't know much about amps, so I bought a Total Airhead (It was an amp, so I assumed it could power a DT770 as far as it would go). Around this time I also started to experiment with higher quality sound files and bought an X-Fi.
Then I decided I wanted two pairs, for gaming and music. The second was a Denon AH-D5000, which I like. After that I decided to get a dedicated amp for it, which I recently ordered and isn't here yet.
As soon as I get more money, the story will be continued...
(After finishing that I realized it's quite long, but I'm really bored)