My party has recently encountered a Slaugth in my homebrew campaign, and have decimated thefoul Xenos (Righteous Fury with bolt pistol ftw). The problem now is that they have it's Ripper Ray, and some spares from the Rogue Trader dealing with the Slaugth, to pass on to the Mechanicus. Obviously they're goignt o want some money for their efforts, so wat kind of price would you put on one of these devastating xenos pistols?

Since Eldar Weapons like Shuriken Catapults go for about 3.000 Thrones, I would assume the same...
... if they would "want it " instead of "wanting it DESTROYED". This stuff is pretty corrupted and pretty organic.

By the way... did they smuggled it or did the Inquisitor allowed them to keep it? Or was his permission never sought out at alle?

*bows at mention*

I want to keep mine though, see if I can adjust the ammo for one of my numerous pistols

Due to the biomechanical nature of Slaugth tech, they might not take it at all. Pretty nasty stuff I think. If they had to they might give a few thousand but your buyer would either have links to the Ordo Xenos and would be concerned with discovering weaknesses or might be an Organicist that tends dangerously towards Xenophilic tendencies.

Well...after some thought the Mechanicus interested does not HAVE to be "xenophile" or "radical".

I could imagine the AdMech to study alien weapon in order to "know your enemy"..and to test the blessed defenses of the machinegod against these vile profanies

Oh of course. However they would be very interested in where you got it and would be rather repulsed by the idea of personally having to handle such blasphemy against the Omnissah. He'd probably have some tongs handy.

The weapons are spoils of a fight between a Rogue Trader dealing with a Slaugth. They are well aware that being caught with such weapons in public and such would be dangerous. At least, I'd like to hope they are. Their Inquisitor is an Ordo Xenos, possibly Radical, so they won't be in too much danger if when caught they hand them over to her.

well it would be hard to sell it as the Slaught are codified Xenos Horrificus and thus all evidence to their existance (including their weapons and anyone having dealings with them) is to be purged.

But if they do want to sell it and can find someone willing to buy my guess would be around 5-6k it has practifally the same profile as a bolt pistol though sligtly shorter range and rate of fire with increased damage and clip size but the best thing is that the it does not require ammo as it uses that firer's life force as armonition (which will according the the discription be the ultimate undoing of the bearer).