I don’t shoot enough factory 9mm to generate much brass. Few leave it laying at my range. Buying brass allows me to choose which headstamp I want and to assemble 9mm handloads which is 90% what I shot in my 9mm pistols. No longer is it purely a question of economics but rather a combination of economics and supply. 9mm fmj is $30 per 50 locally if it is even available. Even when buying brass I can assemble decent handloads cheaper than that price point easily.

GunBroker has brass all the time... prices are often very good.

FWIW

Chuck

There's a guy on another Sig forum, forgot the name of the forum, who has brass for sale on a regular basis. He gets it from a police range IIRC.

I haven't reloaded in about three years, but I was happy with this outfit.
https://store.tjconevera.com/brass.html

If you're still looking, I would check out the Reloading sub on Reddit. Specifically, I would look at the instructions for getting on the Discord. I see brass and other supplies going on a daily basis. Hell, I see primers going semi-regularly.

https://www.oncefiredbrass.com/index.aspx

Commercial once-fired @ $25 / 500.

Here's a partial list of the crap I throw in the dumpster....
Maxxtech
MXT
FM
Aguila
Ammoland
ZQI
WMA
Xtream
A USA
Troy
GFL
NORMA
DoubleTap
TECH
OMPC
Perfecta