$25 on a Dual 502 that I rebuilt. Plays great and sounds very good. A free Sony PS1.

$200 for a pair of AudioEngine 2s, attached to my desktop PC. 80% of the time, I just let these suckers rip instead of firing up the big rig.

I spent about $20 to get a better cable to connect my CD player to my headphone amp. It made an obvious difference that greatly improved the clarity of what I was listening to. Oh, and the headphones (AKG K702) cost about $230 and are a wonderful way to listen.

A set of headphones. From past experience I never thought of them as high-fidelity, except for the esoteric ones and I couldn't afford a pair of Stax. Then I took a leap of faith and bought a pair of Grado SR225i from the web because I needed a pair for late night use and the boards raved about them. What a revelation. True hi-fi at a decent price. I think I paid around $200. Best bargain I have ever had.

An NAD 7020 receiver, a thrift store purchase for only $25.

Marantz CD5000 ~$200.

Gainclone Kit—$150 altogether. There is simply no other product with a better value for money.

How about free? My biggest freebie was a McIntosh MSD4. It runs my two-channel bedroom setup, and I love it.

Elrod Power Systems Statement power cord

Musical Fidelity V-DAC @ $299. Best bang for the buck ever.

Second-hand, it was a Leak tuner for less than $40. New, it's a Beresford Caiman DAC for just over £200.

Two things, actually: Zerodust stylus cleaner for $70, and the Mint LP Protractor for $120. Both seemed ridiculously overpriced for what they were at the time I bought them—but now that I have lived with them, I would gladly pay twice the price if I had to buy replacements!

My Graham Slee "Gram Amp 3" moving-coil phono preamp. Works well with my LOMC cartridge.

Audiosector gainclone kit.

This is a trick question, right? True happiness in the field of high-end means spending big bucks. That is why I disengaged a while back and just enjoy what I already have.

I paid $100 each for NHT Super Zeros. There were a close-out at a big box store—sweet! I later bought an NHT SW2P subwoofer from an installer to go with them. He wasn't actually a retailer. This (with the amp) was $600. I'm still enjoying all of them! BTW, great question!

Rotel RC 1070 preamp that cost US$700. I was eating my heart out because I couldn't afford a $5000 NZ one, but the Rotel was such an advance on what I had. It now drives Martin Logan Puritys without a hitch.

A better quality AC outlet, Shunyata's SR-Z1, $75. This improved my entire system.

Jon Risch DIY sandbox for TT isolation (search at audioasylum). I used scrap lumber in the garage and bought a bag of washed playground sand. This $5 investment nicely tightened up the bass.

HeadRoom TotalBitHead—it still blows me away. $149 and good, wait, great, sound from my five-year-old laptop running Ubuntu and my AKG 701s. If I were a student, this would be all I wanted. Except maybe vinyl, and a record player, and...

$475, for a Ray Samuels Predator portable DAC/headphone amp.

$30 for 10' of DNM speaker cable. Best investment evar!

Hands-down, the Acoustic Energy Aegis One speakers. $299 for the pair. Best investment I ever made.

Headphones: Grado SR60.

Apple Airport Express!

Pro-Ject Debut II

Fake Persian rugs to hang on the wall to prevent slap echo.

That's easy: the $200 I spent on a Tivoli Audio Model One. Some people may not be aware of it, but you can connect it to a preamp via its record output and get a very good stereo tuner. (Yes, it does output FM stereo!)

Bel Canto Dac3.5 VB and ref500M.

About $500 USD (price was in Swiss Francs) for a refurbished, second-hand headphone: a Jecklin Float Electrostat. One of the finest headphones ever built, in line with the best Stax-headphones. Original price almost 30 years ago: $2000 USD.