I've got things lined up so that my players are about to negotiate with Stryxis trader for details (location etc) of a lost Xeno treasure but I'm a little at a loss as to think what the Stryxis will want in trade.

I want to play up the fact that they don't measure value in the same way as Humans (or in any reliably discernable way…) but I don't want to trivialise it.

Also the meeting will be interrupted by (anti-xeno) Imperial authorities so dealing with the humans and "saving" the Stryxis may count favourably towards the deal - but likewise I don't want that to be the only "price" the players pay.

Any suggestions for what they could demand? Anyone come up with creative Stryxis deals?

One of my players wanted a Hell Rifle from the Stryxis. They in turn demanded a Grand Cruiser. Eventually he talked the Stryxis down to a raider they were looking to offload anyway.

Another one of my players wanted access to knowledge about Daemons. His price was to mind wipe some captives that the Stryxis had.

My Arch Militant wanted a space marine land speeder. He was forced to trade his chrono and his keepsake bolt shell casing.

Everytime my group has encountered the Stryxis, someone has lost a watch. I keep myself mildly amused with this fact. Usually it'll come after a round of negotiation as the final bid from the Stryxis as "… AND your chrono, or nothing!"

I've taken a literal pound of flesh, before. The Stryxis were quite amicable about their request, taking pains to ensure the process was painless, no major organs were affected, and both parties agreed that the weight amount was correct. The character was rather annoyed when bodyclones of him started turning up several years later.

My wife came up with a possibly great (and suitably weird) idea this morning - they demand a very mundane (and slightly personal) thing - but ALL of the ship's complement of it:

"Give us your hair."

"Wha…"

"All your hair from all your bipeds."

OR

"All the wax yof your ears…we want it"

Her original suggestion was everyone's belly button fluff - perhaps the Sryxis can answer teh ultimate question of why we have it…

What about demanding the imperial survivors from the attacking force that the players might have captured, plus a number of "biological samples" from the explorers themshelves for "scientific study"?

Acting-Captain Marzu : I'm told that your species can produce soldiers by demand. I will be waging a war soon, how much for an army?
Sire Blue Sun : Yes, yes, honoured biped! We can grow you much meat, strong and clever as the Acting Captain wants! And all we would ask are the gametes of all your crew!
All : * clutch themselves protectively*
Sire Blue Sun : Think of the strong and clever meat we could grow from the Honoured Acting-Captain's friends!
GM : Shall I resolve the results of the mutiny now or later?

This happened in our campaign Eventually Marzu talked them down to samples from some of the crew

My players offered some beastmen slaves, which the Stryxis were quite curious about. "Now is it a beast or a man?" - "Baaaaah!"

Just prior to their first encounter with the Stryxis my players had boarded an Eldar frigate and had taken some prisoners in the process. Upon finding out that the Stryxis hate the Eldar they suddenly all had this crazy look on their faces. Yeah… they traded one of the captured Eldar for a Relic Boltgun, an Omni-Scope and some haywire grenades… guess what's gonna happen when the Twilight Swords find out about this…

I had a stryxis asking for either 7777 slaves, the captains upper torso a priests tongue and a left ear or the captains family power dagger.

One of the things they managed to get from my players was being permitted to kiss the Lord-Captain's pet Ambull.