Best bang-for-buck purchase you have made?

Monarchy Audio M24 DAC and preamp. My ACI Sapphire XL speakers also make a great bang for the buck.

I think I would vote for Odyssey audio with their mono extreme se amps and the man behind the scene Klaus.

A "Trends Audio" USB to AES/EBU converter for about 200 bucks to attach my laptop to my Zanden DAC. A bit more expensive than the Hagermann, but creating less listener fatigue after long listening bouts, for reasons I still have to find out....

Nuforce Ref 9 SEs.

Linn turntable,dynavector 505 arm and dynavector ruby cartridge all thrown free with my first major purchase of electrostatic speakers and threshold electronics 30yrs ago.
Otherwise, a (tested) perfect luxman R117 receiver with remote for $125 on ebay and my (9/10) magnepan 1.6 QR speakers for less than half list price.

Addendum:
Two pairs of Apex signature speaker wires (purchased from on line reviewer) as well as my Cogen Hall EM digital cable. ( I will never part with these cables). In retrospect, these were more of a gift than a sale from the prior owner.

NOTHING! --- I pay through the nose for everything! :)

When Federated stopped carrying Luxman equipment, late 70's early 80's ?, the West LA store blew it out at more than 50% off. I bought the T-12 tuner; C-12 preamp,and G-11 equalizer for $825($1785retail) new in sealed boxes! I used a Dynakit Stereo-70 then an Eagle 2 to drive Sonab-116's and later Dalquist DQ-10'si

Without a doubt my Channel Islands Audio VDA 2 DAC. Exceptional sound and build quality for $599. The price to performance ratio is high, you will spend much more to obtain better sound. I felt that it sounded better than the Benchmark, which while very good has too many bells and whistles for my tastes. In addition the VDA 2 uses a fully discrete analog out.

a pair of khorns for 1000 dollars, not a speaker for everyone but i luv them.

a brand new pair of fosrex fe126e 4 inch full range drivers for $90. hooked em up as full range and supported the bass with a sub,real hard to beat!!!!!!!!!!!