Haven't ordered from him in a couple years, but used to deal regularly with a guy who sells on eBay as childhood_dreams (yes, a weird name for bicycle spokes).
He's an old school old guy who used to stock only Sapims and has the cutting and thread rolling machines to give you exactly what your build requires (mixed length orders are no problem). But nowadays he seems to be selling "unbranded" USA made stainless spokes, still cuts them as you specify (so do the calculations carefully and re-check 3X before you order, he's never screwed up my order, but I have!)
For example: double-butted silver stainless spokes (2.0 mm butts with 1.8mm center) with choice of silver or black brass nipples (in either 12 or 14mm) cut to any size from 300 to 170 mm comes to about $1.05 each.
Sure that's not the 38 cents straight-gauge deal from Porkchop BMX but...not bad IMO.

EDIT: checking the current ad for PorkchopBMX the "Richman" stainless spokes they are currently offering (cut to your specs and with NO nipples) for 36 cents plus tax are made in Taiwan, not USA.
Probably fine quality spokes but Taiwan isn't USA (not yet, anyhow).