I have placeholder leather on the market for while I'm out of town, and I don't know if it has sold or not. However, I do know that people have questioned my price several times.
It is sitting at 200 souls for a stack of 64 leather.
I think that the price is justified, personally. As Xelerator1 and Witch have said, breeding cows is an intense, tedious process. The amount of thought alone that goes into attempting to breed sustainably and with a high return is probably more than the average non-farmer Herocrafter ever has to go through.
As a farmer, you can farm cows for four hours and have exactly four stacks of leather (lucky night I'm referencing) and know that you will have barely met the needs of a quarter of the town members. At this point, you can undercut for a loss (What feels like a loss, based on time spent compared to if I had just punched wheat.), or you can hand them off to be enchanted to an enchanter. At that point, you can then spend 45 minutes per set trying to get enchants worth a profit, however in
minecraft survival servers, considering you've just revealed you have four stacks of leather and must donate at least half to the town, you're now in the hole on time spent vs. profit. Unless you're also an enchanter, at which point you can then invest 400 souls or 200 souls (codexes/relics) ONE WAY to switch to the enchanter...again, which puts you not only 4 hours deep into the leather, but also 200-800 souls deep into profession switching, not including enchanting time.
THEN you can put your product on the market and have it bashed for being overpriced.
I personally thought I'd make ends meet by selling off the cooked beef on the side, until I saw a stack of 64 for like 2 souls on the market. Which is now more time and effort on my side as I need to find a hungry town willing to buy in bulk just to effectively unload it.
I get several messages daily asking if I have any leather for sale, and as Witch said I usually just produce to order for my town, so I don't normally have any on hand...Which, why would I? I've gotten offers of 30 souls a stack, wanting 3-6 stacks right NOW expecting me to hop my happy arse down to TD and roll around in my 180 souls for 6 hours of work like I just hit the lotto.
I have yet to sell a single stack of leather. (Sans marketplace sales I'm unaware of) It goes right to my town, because at least there I know I'm getting some of my effort back in compensation gear.
Long story short, I think the price of many goods is UNDER market value considering time spent and invested. 25 souls for, presumably an unenchanted leather chestplate, seems perfectly within reason, to me.
(Caps for emphasis cause being on mobile sucks.)