I have just been reading a book called Debt by the anthropologist David Graeber - it's a fascinating book, examining in some depth the forms that states, markets, money, credit and debt have existed in. This has prompted me to ask some questions of Angband's economy, some of which I am sure are entirely superfluous and others which might prompt some useful, gameplay-improving answers.
So, first: Angband's economy is based entirely in gold coins and the convertibility of precious metals and minerals directly into gold coins. Note that the game itself never says that you have any gold coins: just so much stuff that is equivalent to so many gold coins.
Where is the adventurer finding enough space to carry (at the beginning of the game) enough chunks of copper to the value of 213 gold pieces or (at the end of the game) enough chunks of precious minerals to the value of tens of thousands of gold pieces? That much stuff would weigh you down. I think an intelligent player would try to maintain a certain amount of tradeable currency, but not pick up everything they found.
Also, the amount of gold that successive adventurers would bring up from the dungeon would surely cause massive inflationary problems...
And why does everyone in the dungeon seem to be carrying around so many precious stones all the time? Their needs as troops (food, water, weapons, armour) will surely be met in some semi-centralised way, since Morgoth needs an army that can fight, that is well-nourished and the like. So in everyday usage, soldiers would make no use of money or precious stones. Why are they carrying them?
Also, how does the town even exist? It is a weird place, atop a massive dungeon full of murderous individuals, all looking to profit from looting and pillaging. The town is nevertheless full of other people, none of whom seem to be particularly interesting or adventurous, all of whom must survive somehow but clearly do not possess the survival skills to fight even a moderately well-equipped player. These people must all eat and sleep somehow. They must also be occupied one way or another. Who is paying them to laze around in a position of extreme danger?
The player has an unguarded, unprotected home in which they can place whatever they like and be sure that it is there even though the building is unoccupied 99% of the time. How does it not get broken into?
Also, why is is cheaper to buy arrows than food? Why are cloaks cheaper than food? Food is essential for life. The idea that a ration of food should cost four gold pieces makes the real-world inflation of food prices look seem tiny by comparison. And why is food handled in-game but drink not?
Why does the player not simply demand what they want from the shopkeepers and threaten to kill them otherwise? There is a total lack of authority or protection to keep this from happening. There is no reason for the shopkeepers not to kill the player, either.
I think a lot of the weirdness of the Angband economy comes down to this: we are all very used to exchanging money for other things we want or need in shops, in line with the rule of law. However, the situation that lets us do this (state authority, police, judicial systems) is pretty much entirely dissimilar to the situation in Angband.
Actually, the entire system of tradeable commodities that Angband has is completely unfitting to the place the game is set. The idea that you can have seventeen identical longswords is somewhat ridiculous, or twenty pieces of plate mail - these things historically would not have been available for trade. You would, at best, be paying someone to make them for you, to your specification. Smiths would not have created massive surpluses because there would have been no reason for them to do so.
That's all very well, but...
So what might happen if we try and provide more reasonable answers to these questions? What happens if we try to re-balance the game's economy? I think that some gameplay issues might start to disappear, mostly those around gold availability, buying, and selling.
From the list above, I would start off with:
1. Make currency weigh the player down. Allow them to drop it, pick it up, etc.
2. Reduce the amount of money that monsters in the dungeon carry, significantly. Some monsters should hoard lots of money (but should maybe not be carrying it - think dragons) but most will have none. The current scaling of amount of GP / drop with dungeon level will need to be rethought.
Pair this up with a reduction in the amount of money required to purchase items. EyAngband started doing this quite well.
3. The home should either be a general item-deposit place that holds your items securely for an access fee, or it should be a home that requires you to pay a retainer to guard it.
After this, what? I think food and drink need to be reconsidered - either they need to become serious elements of the game or they need to disappear. The shops need a plausible back-story; are they all merchants, bringing wares to flog to needy adventurers, or is there a permanent weaponsmith, potionbrewer, etc in residence all the time? How do they survive?
These questions affect the gameplay decisions around them. If the weaponsmith's is actually a weaponsmith's, then maybe you can ask them to make you a new weapon for a given price, but they are unlikely to keep hundreds of weapons in their store. But if they are a merchant, they will surely want to bring some impressive swords along with some cheaper ones - but maybe they will only part with them for a large sum. They certainly wouldn't bring 18 whips and 18 daggers.
Maybe, also, the player could leave a deposit on a particularly handsome item and come back for it later with more money. Combined with a reduction in the availability of gold, this turns into less of a scum-fest and more of something with the potential to be an interesting minigame.
Merchants would also be unlikely to buy unimpressive weapons or items - their job is to turn up with wares, flog them and get lots of precious stones and metals to take back away with them. Unimpressive weapons are worth less to the merchant than the equivalent in gold pieces, because the entire point of the trading is to exchange weapons for more liquid assets. There would have to be regular trips away from the area in order to get more stock and deposit money with a bank, out of danger - this provides a nice explanation for shopkeeper rotation.
And why the hell would there be a temple above Angband? On this thought, I'll leave you.