Best "Bang for the Buck" you have owned?

Yes, the CJ ART, various Audio Research were all great...but I do remember lower priced items that gave much pleasure for their price.

In no order, The Large Advent,  DQ-10, Nakamichi SR receivers,  inexpensive Nordost cables, many tuners giving good vibes vis "FREE" music.  Also, in a different way, the Nakamichi TM radios and SoundSpace systems. 

There was a solid state ARC pre that was very

And I do  remember "free" listening at some friends homes/systems that were great values. I was exceedingly lucky to have a best friend that bought most of my gear when I was "moving on".  It gave me the chance to listen to what I had had compared to what I currently least once what I had sold to him was better than what my replacement gear was...........the old "live and learn". 

A Schiit Loki. Best $150 ever spent.
I bought a NAD 118 digital preamp. It is a cross between a Schiit Loki and Black Ice F360. I bought it, brand new, at half the full retail price of $1600.
Five years later, I bought an immaculate used NAD 118 for around $400.
It’s fascinating to see what’s old is new again in these forums.

Mr. Clean Magic Eraser was discussed for several months c.2007 or so, I can’t recall the exact year. The upshot was that it was generally enthusiastically endorsed among the analog cognoscenti as a method for cleaning a stylus.

Use it dry. "Dip" the stylus into the material a few times. Don’t rub.
Thanks ... I have my Onzow gooey bubble, but I was curious...
ESS AMT Tower 1's for $120.
Advent OLA's for $60
Snell Type A-ll for $400
Thiel CS.5 for $175

Listening to any pair in the above list brings a smile to my face. 

But the b.b.b. of them all is my pair of DQ-10's for $350. The seller couldn't find the passive XO for the sub and offered me a preamp in its place. Told him I already have three preamps. He said it's a lot more expensive than the speakers I was buying and if I wasn't happy with it, I can sell it on eBay and make some good money. He even promised to personally deliver the XO to my house if he finds it. The music room was not well lit and can't make out the preamp but it looked old school. A preamp for a cheap passive XO?  I told him he's a very nice person but a terrible businessman. We both laughed and shook hands. When I got home, I found out what I had my hands on- it was an ARC- SP6. Until that night, I didn't know a thing about it. I spent most of the night reading all I could find on the net about it and ARC. I keep everything I buy so no, I'm not making any money from the gentleman's graciousness.
Easily my JVC RX8020VBK home theater receiver. I bought it in 2002. The budget was tight then and I found it at Costco for $285. 120 real watts per channel, it's had 18 years of hard use and never missed a beat. Everything still works perfectly without the slightest problem.  It replaced a JVC tuner/amp combo that I've had for more than 30 years that still works. It's getting a little long in the tooth on the technology front; S-video switching instead of HDMI and I am starting to think about replacing it in order to get Dolby Atmos. I'll have to think of a new mission for the JVC, perhaps a dedicated vinyl receiver (it has a phono preamp built in!). There's no way I'll ever sell it.

I'd buy another JVC in a heartbeat, but alas they've gone out of the receiver business. That's why it was so cheap in the first place. But as far as bang for the buck on a piece of new equipment, it stands out as the most satisfactory consumer electronics purchase ever, out of a LOT of contenders. I should be so lucky with my next one.
I apologize for listing this one, it’s the show stopper, and some of you have heard about this one before:

A MFA made Octal tube based original Venusian Prototype three chassis (Line/switching, Phono,and power supply boxes) full function preamp. Swings a clean + 170 volts. Just an insane thing, it is. Best tube based preamp vittles ever tasted.

$108 bucks. Found on eBay, no less.

I beg forgiveness for using it so little. If I cleaned it up, re capped it, and did a few of the more modern additions and alterations to it, etc...I’d think it would be a top contender for being right at the peak of preamp development and quality. (you will find pictures of it on the net, if you search it out)