About merchants.
I have idea how to do that the wolves were fed and the sheep were safe.
Lets they buy all stuff (beyond their specification) but at greatly lowered price - first item for 75%, second for 50%, last for 25%. To prevent player's cheating, when the first item will be most valued one, let it be set of a tree, sold at (75%+50%+25%)=150%/3.
Lets this option will be allowed after you make some business with merchant, maybe some minor (or not) quest, or if you have decent Mercantile skill, or Persuasion x1.5 from Mercantile skill.
Maybe not all merchants can make a deal like this - this nice young lady gladly buy from you all scrap/crap you found besides electronics and energo wepon she usualy trade, but THIS old goat will NEVER accept it.
About money. I still think there are too much money in game.
We need cut off at least 1\3 of selling price, and add a sinkhole for money.
Like for to get information - it's most valuable and therefore expensive resource.
Such information does not have to give serious advantages, maybe only minor, but can get more flavour to a game -something about Underrail past, or about past of some NPC characters.
Money to buy unique things (wepon, utility, antique trinkets), money to bribe, money to buy safety, or new hidden pathway.
Maybe someone, the really shady pro watches over us, and carefully calculate all money we accumulated?
And he is going to rob us just a little? Just little script scene with various consequences - robbering, fight, partnership?
About crafting
I can agree with what Mindless said.
Except
Pure Psi-Caster: From zero to big investment into Electronics(Psionic Headbands); medium investment into Biology(almost all psionic gadgets need this!); from zero to medium investment into Mechanics(Tactical Vest), from zero to big investment into Tailoring. Min - 1 discipline, max - 4(!!!).
for pure Psi you'll need only leather - to hide and sneak, and to fight and (can not choose the right rhyme

) and
150 crafting with 10 INT, and +1 can be achieved with Junkyard Surp.
JS can roll +2 stat, so bonus is even bigger.
Btw about JS - I consider it like test item.
I feel like we have strong buff for nothing.
I hope it wiil be deleted from game, and Chemistry+Biology will do the things.
Or at least set new price - min 100 charons, not 10 or 30 like now.