Your rep with the faction alters the amount they ask for.
I mention that because I have had the lowest or second lowest rep rank ask me for palladium donations.
I noticed that when they offerd amounts like ~20 or ~40 then when I level the rep it became more until it capped out at 72 and 108.
Which is great as thats 8k merits for 108.
Finding somewhere that offers the missions (donations) is a pain.
I did my searching based on the ingame "Produced by" and "Consumed by" thats mentioned in the market blurb and on inara I think which takes the blurb from ingame.
Palladium
Produced by: Extraction
Consumed by: All except Agri, Refinery, Extraction and Military
The all ecept part is a wierd way of putting it.
The bad things Ive notice are that War, Outbreaks etc mean that the Factions in said states ask for items related to those states (weapons or medcines or food). I havent really notinced any state that asks for metals. I think its just based on the Station ecconomy - Faction Ecconomy and a none state.
This is all just guess work though
I really shoudl proof read these this is like the 10th edit