Cabella's has 500 rounds of Wolf 7.62x39 for $114.99 + shipping or 1000 rounds for $219.99 + shipping. I haven't checked at Cheaper Than Dirt recently but they're ammo is usually a little cheaper than Cabella's.
I bought Russian and Chinese 7.62x39 locally for about 9 cents a round as recently as 3 years ago, but those days are probably gone forever. I'm down to less than 300 rounds and have cut back on shooting the SKS just for fun because I can reload for my 6.5x55 Swede Mauser and the .30-30 for less than Russian SKS ammo costs these days.
And that's only because I still have quite a bit of bullets, primers, and powder that I bought several years ago. By the time that's been shot up reloading components will probably cost more than factory ammo costs today.
Scouts Out! Cavalry Ho!