Least expensive discrete resistor ladder NOS DAC?

The Schiit and Soekris dacs aren't NOS dacs, they are r2r but oversampling.

In your budget you want the Holo Audio Spring, level 1 or 2:

https://kitsunehifi.com/product-category/brands/holo-audio/

I'd also definitely look into the new Metrum Onyx, it may be a bit above budget but Metrums are very high quality, and the new dacs use all new r2r fpga modules.

@tommylion, Metrum dacs (Onyx, Jade, Pavane, Adagio) and Holo Audio Spring all use discrete resistor ladders and are NOS. Soekris also uses their own discrete resistor ladders, and going by George's post, has a NOS mode, I'd definitely consider their flagship dac 1541, which is way less than $2000.