What is the best value you have encountered?

Carver Silver 9t monoblocs 900 wpc @ 8 ohms--$1200 used

Luminous Axiom passive preamp $150 (it will blow you away)

Signal Cable Silver Reference speaker cable and interconnects.

Any used Shahinian speaker; I picked up Obelisks for under $1,500. Any VTL amp; I found 300 monoblocks for under $1,500. Two Rotel CD players for $10 each at resale shops. An Accuphase E-202 at an antique shop for $25.
SMGa speakers for $40 at a resale shop. Any used Klipsch speakers and any used, but recent Decware amps. See Triode Electronics for NOS tubes unless you can find them in "antique" shops. Always ask for any cables to be thrown in, the worst answer is "No" and you may get Kimber KCAG interconnects for free like me.

Bought a used McCormack DNA-1 for $800, used it extensively for 8 years, sold it fo $750.

Or used Purist Audio Colossus I/C's & wire; sold for gain after almost 10 years of use.

Apogee Stage speakers. I bought a pair in 1995 new for $2,500 & although I no longer have them they still do wonderful things I have not heard since.

I just purchased a set of vandersteen 1b speakers for $144.00
That is my best value purchase to date.