I haven't been shooting much 7.62x39 lately, but was checking prices today. KIR ammo out of Texas, has PPU brass cased for $0.439 per round, which isn't bad for brass. Relatively new company online, but from what I can tell off of ammoseek, it has good reviews. Thought I would pass it along.
PRVI PPU 7.62x39mm SAME DAY SHIPPING 123 Grain FMJ Non-Corrosive NO LIMIT - 15 Rounds (Box) [NO TAX outside Texas] - KIR Ammo
PRVI PPU 7.62x39mm SAME DAY SHIPPING 123 Grain FMJ Non-Corrosive NO LIMIT - 15 Rounds (Box) [NO TAX outside Texas] - KIR Ammo