I get russian steel by the crate and yugo brass on stripper clips by the crate. Real cheap and something like 1200 rounds for $169 delivered.
The yugo on strips is ideal for the SKS because you just grab a strip and load.
I get Herters/wolf/brown bear from cabelas for 1.99/20. When I want to shoot a lot and plan on detail cleaning the gun, I shoot corrosive. When I just shoot a little and plan on running a snake and calling it a day, I shoot wolf/non corrosive.
Don't buy brass unless you are shooting to find the most accurate stuff or hunting.
The U.S. made ammo for x39 is under loaded, just like EVERY US made ammunition.
The old yugo is the best IMO.