Best "Bang for the Buck" you have owned?

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)

Bought a set of Linn Keilidh for $120 in excellent condition 4yrs ago. Purchased from a big Linn Fanboy - guy had Kabers and Keltiks too all running Aktiv. Have been very nice little towers running with a variety of integrateds. So just got my Cary, 808R back from NC getting totally run through and brought back to spec. Paired it with a Sonic Frontiers SFL-1 and a Rega DACr for streaming and plugged in the Linns. Man, the tube stuff really brings out the absolute best of these little wonders. If u can find a set for $400-$450 I’d say grab them especially if your into tube gear. The Cary in Triode @ 30x2 pure “A” is a very good amp but, the integrateds I’ve used by Tandberg and Perreaux have been a good fit as well. Point: Linn Keilidh for $120 easily the best Bang for Buck story I have to share

My 1983 aiwa ad f770 cassette deck. Paid $550 for it brand new 38 years ago, still kicking like day one! Only thing I’ve had to do was change belts....not fun, but worth it. I play it all the time. A beautiful machine, and back then, before it’s time. It will never be sold. Bought a back up f660, just as good a machine, works wonderfully. Sold my f990 as it was worth more, plus did not do anything that the other two decks are not capable of.
Secondly, my discwasher system, also from the early 80’s. I’m still using the same record brush and stylus brush included In the kit. I still have some of the original fluid left. Loaded up on original discwasher stuff when available on ebay. I got enough to last me until I’m dead.