Used to other breeding sims and from experience with say, Wajas and Gaiaonline,  before I try to sell things, I'd like to know what some of the odder or harder to accumulate items are worth. Not keen on looking like a dork over pricing things or like an easy target by under pricing them.

The current items in question are the various jewels, I've got a sapphire and an ameythst instock, rubies seems fairly common since I regularly find those, I've got Living Wood, and I'd also like to know what Warehouse lvl 2 and 3 usually go for.

i recommend you search in item trades or in exchange items tabs to get a sort of idea....but the prices in item trades can fluctuate a lot since its auction based so i suggest you check out the guides too on the forum and if you intend to sell any of these then make sure you put the auction parameters properly so that the value can settle close to demand :)

try to trade for energy drinks

but don't use them! they'll go for a lot on the trading tab

also, living wood is at least worth an energy drink or two, that's what i've gotten for them

Living wood is super rare. I would have an auction without buyout, you'll get more bids that way.

Demand for tack workshop jewels and other items is always high. Rainbow jars and energy drinks you're looking at about 75,000

Having no buyout is a good way of guessing median prices, but if you want a quick turnover just make a fair buyout. Crocotta fur is about 2k, bones are 1k, black oil 3, I sell living wood at 4.5k (I just find a ton of it personally) and it doesn't all get sold, energy drink 7k, mutagen 6k, amnesia potion I sell for 12k but you could get more, leather 3.5k, cyromorph chiten or whatever is 4.5/5k, elegant feather 4.5, white feather 2.5-3k, plain feather 3k, biogas bubble 2.5k. Backgrounds go fast at 20k, and sit around forever at 29k.

Yes, you could get more by waiting a few days and not having a buyout. But I've been able to turn over nearly 300k profit in one sitting just selling off my accumulated explore inventory for having fair buyouts like the above. :)