If I had to put a price on it, I would say it's worth about what standard 762x39 ammo is, and only because it may have some collectability or interest in it for being unusual. That being said, many don't like the extra step required to clean after corrosive ammo. I don't mind it at all in a bolt action rifle, but in a semi-auto like an AK or SKS it's a bit more hassle.
Maybe put $30 OBO as a list price. Just a suggestion.