New DM here running our rookie group the LMoP. What do other DMs have their players do with the non cash loot? For example, "30 Beaver Pelt's worth 2GP each".  Is it supposed to create a dilema for them?  To make them wonder, Is it worth carrying this with me until I can offload it? Are some of these items useful later on? Do other GM's just let them "insta-sell" them for the cash value? Do you make them cart them to a shop to sell them? 

Ideally, they should be spending all their loot on consumable items like potions and spell scrolls, while the wizards in the party buy spells for their spellbooks and acquire material components that cost gold. As for the actual process of selling off non-coin loot, you can go either way. Some DM's just hand-wave a "shopping/selling" trip to the local market to cash in on the art pieces and other bulk items, others make the party seek out buyers for strange or specialty items.

In games I play in / run, any non-magical "trade good" (not a weapon or armor) sells for full price once you can find a suitable merchant. Weapons and armor sell for half. Magic items are handled with persuasion checks to be anywhere from 150% to 75% cost. I use a version of the haggling rules that James Haeck put in an encounter a while ago. Starting price is 150% list. Players can make persuasion checks to reduce the cost, DC is the merchant's passive persuasion. Success reduces by 10%, every 5 over is another 5% off. Merchant stops haggling when the players fail 2 or 3 checks in a row or get to 75% list price, whichever comes first.

for some of the more exotic, but not necessarily magical things we find, I try to come up with common or uncommon magic items that could be made out of it, and then reduce the cost by the value of the component and the difficulty of the skill check to make it.

Ale and whores.

Typically, at my table the players prefer to just convert “vendor trash” to gold immediately, they don’t want to track 30 beaver pelts, two small figurines, three rings, four garnets  and one aquamarine etc etc etc. If the item is described as “Thing worth $X” then they just write down $X. 

They write down the specific item when I describe the use of the item and not it’s price. 

I would make my characters track weight/carry factor for something like 30 beaver pelts (my players decided to leave them) since that would affect their movement, and potentially dexterity if surprised, IRL. Otherwise I tend to just let them take things and sell the (non-magical) items to the first non-specific vendor (i.e., an armorer isn't going to buy scrolls, etc.)

Personally, unless they have the appropriate appraisal skill and pass a check, Ill tell them they have no idea of the value. If they have the skill and fail the check, Ill give them misinformation.

Ill know and record the value however, then when they come to sell it, theyll make a charisma check. Ill calculate 60% of that value (if the buyer is in the market for the item, 35% otherwise), plus 1% for each point they succeeded their check by. If they fail the check, Ill calculate 60% of the value (if the buyer is in the market for the item, 35% otherwise) -1% for each point they failed by. Either this result (rounded up) or the buyers total expendable wealth is their maximum buyout.

Ill then secretly determine the NPCs reaction, positive results equalling a more fair trader, and negative results equalling a trader more prepared to rip you off.

Haggling then ensues with reaction rolls a plenty. Its a nice little role play opportunity, as well as being an incentive in both the appraisal skills and the charisma stat. Its also hilarious when the players find out that small, crappy painting they decided to drop for encumbrance purposes was 10x more valuable than the big fancy one they took, just because they didnt bother investing in a cultural appraisal profficiency that wouldve told them it was by an incredibly famous artist who dies two decades ago 😂

Other than that, it adds carry weight and bulk points to their character.