ToME WikiHugoTome: Currently the assumption is that money is useless beyond a certain character level, and therefore a) it doesn't matter that it is possible to get silly amounts of money, and b) it *does* matter if a proposed new feature would make money more useful in the later game.
This seems a bit upside-down to me, and I think the primary problem is the unrealistic behaviour of shops: they have a per-item limit on the amount they will pay for an individual item, but have no apparent limit on funds available. (And if you have 30 ego arrows they will happily buy all 30 even if the total payout is way over their per-item limit.)
I suggest therefore that merchants should have an actual amount of cash proportional to their maximum payout (say around 10x), that this should decrease whenever they buy something from you and increase when they sell something, and that as time passes it should also gradually normalise up or down towards some comfortable limit (possibly the same as their starting cash).
This might also make it possible to allow a max-per-item greater than 30k without unbalancing the game; not sure about that.
My 2c and counting.
Actius: There's lots more that could be done with merchants, depending on what you're trying to achieve. For example, you could have market costs change based on supply and demand. You could have some kind of random "behind the scenes" model for other people interacting with the shops (both suppliers and buyers). You could have eager suppliers reacting to increased demand for certain items by flooding the shops with similar things (at higher prices while the demand is there, gradually reducing over the course of days and weeks if the game lasts that long). You could have system wide or area wide peaks and booms (perhaps with hidden markov models or something like that for chain effects). You could have political trauma (protests, tarriffs, taxes, etc.). You could simulate other characters in the game (perhaps based on tomenet experiences) or you could decide that local towns and such have (simulated) high level characters "running them" with preferences that relate to the player (or the npcs) in some way. For example, if the markets are modeled as if other players are frequenting them, then items sold to the store will tend to vanish before long, and will tend to increase the simulated coffers of the stores. This pushes the balance towards the player having more money available and away from having good items available. If the other direction is desired, then overall prices of goods might drop because there's just not enough demand for them. And so on... most of this complexity probably is not justified unless the game gets a "Merchant" player class.