Right now I'd say it's worth from $250-$300.
That being said - it's kinda a crappy stock. Shorten OAL, but REALLY smashes the cheekbones. You wouldn't want to fire more than a couple rounds at a time.
Contact BadBoyBeeson if you wanna sell... he bought mine and I think he's looking for more. Otherwise maybe contact Casey at TacOrd - if anyone knows supply/demand for shotgun parts, it's him!