exits are NORTH and WEST
That's a little reductive but it's a good headline so here's the nuanced angle: video game economies are always neutral at best and actively damaging at worst.
I think that we should set up some groundwork here: I'm not talking about microtransaction-driven Steam Community Market-like things. We should all know those are exploitative without me having to tell you that. But that's not what this is about - this is a hit piece on Zennies, on Rupees, on gems, on shells, on gold, whatever you want to call it. The fictional money that exists as a resource within games for buying and trading goods. It sucks.
We all know our way around a video game shop, right? We all know what a Pokémart sells - ¥200 for a Pokéball, 300 for a potion, etc, etc, etc. The shopkeeper is a staple of game language. A lot of game developers learn how to make UIs work just for shop keeping. I know I sure did. The shopkeeper is a well-established bit of lore to the point where making them feel fresh is tough, to the point where certain games don't even bother. And this could be a love letter to the gachapon from Magic Wand, or Zacharie from OFF, or the many many shopkeepers in The World Ends With You that really bring the mediocre systems to life, but what really matters here is the systems they are the face of.
I was reading thecatamites's notes on the development of Magic Wand, as you do, and in those notes I came across a section that maybe changed my view of game design as a whole:
Father forgive me for I have sinned, I have put virtual money in my videogame before I knew what it would be used for. Everybody does it.. everybody does it because it WORKS!!! Don't shout at me!!! Everybody... loves... feeling... successful... and everybody... loves... getting virtual... money.
In Magic Wand, you gain money when you break pots - but there isn't anything to spend it on. Or rather, there is but that thing is just... gachapon toys.
Everybody puts virtual money in their games, without thinking too much about what they're there for - that is how systems are perpetuated of course - but looking at what games get out of it... based on the things in my Steam library... not much! A lot of games regurgitate the worldview of their developers, intentionally or not, and most people making the kinds of games people will play are capitalists, and this is most prevalent in the general idea of shop mechanics. There is always work to be done, in exchange for money, and thus people who don't have the money to afford things must not be working hard enough. (This is a capitalist lie, also.)
From a game design end, shops rarely ever create friction, but their presence is also expected, with no meaningful engagement: You either have the money to buy it, or you don't. And you can do something to get the money in-game, usually, though at the end of the day, the intended design is that "having money" is something for late-game players to do, and if you want to experience the game interaction of "having money", you should get to the late-game, usually by which point the things you want are worthless, relative to the story-relevant things you've gotten by virtue of being a player character in a world where die-hard individualists are allowed access to game engines. (MISTAKE.)
It's not that these systems exist that's the issue, it's that they exist and reproduce without examination of why they are perpetuated, and a lot of the time, they're perpetuated in games that would be better off without them. Merchants and traders in the lesser Fallout games feel especially strange - just years after the hypercapitalist nature of humanity brings itself to its doom and there's people out there who are willing to withhold food from the starving should they not have enough bottlecaps? Okay. But if we were here to discuss how Fallout games regurgitate American issues and images without thought we'd be here all day.
And on the inverse, Diaries of a Spaceport Janitor is one of the only games that does something with its economy. It does good to make sure the mechanics of an economy are examined - it's a game about living day to day in poverty, regardless of how many things are happening around you.
But clean cut criticisms of game economies aren't the weird stuff, the juicy flaws in otherwise well-designed games that are fun to talk about. That's different - almost every game shop I'm seeing, from Hylics to Hollow Knight, to The Binding of Isaac and Downwell, a game that otherwise thrives on minimalist design, there's not really any game that comes close to justifying its economies, especially in games where that economy doesn't quite make sense, diegetically.
Hollow Knight is especially weird about this - the land is dying, just below the surface of the last town is a sprawling mess of infected, dying people, people who have lost their sentience, yet there are still merchants, bankers. The systems of capitalism keep chugging, even with Iselda's reluctant and beleaguered shop keeping, and even without workers to fuel them. Perhaps that's a statement in itself. But considering how Hollow Knight's weaknesses reside mostly in the under-designed gameplay, I don't think it is.
In the same vein - Nuclear Throne, I think, makes a good case for eschewing inherent market systems in games, by eschewing market systems in games. It's a good game, polished to a fine sheen, but unlike TBoI or Gungeon, Nuclear Throne's resource management isn't monetary. There are currency-like resources to manage, sometimes trading HP for better positioning, and managing ammo is essential to getting anywhere, but you don't spend radiation for the new things, in a market. Because it wouldn't work, in the lore or in the gameplay.
But maybe your game has that built in. Maybe you have traders, merchants, caravans, even, and you want that resource management built in. There's two kinds of solutions I think work well, though I do heavily encourage you to come up with your own.
The first is multifunctional currency - your currency exists outside of the context of its status as a currency. The go-to example would be Dark Souls, and how souls are a combination of both experience points and currency, but like... you know. So Caves of Qud's core currency is fresh water. It meshes with the worldbuilding and it exists outside of the context of itself as a currency, it's also a fluid that can be used to douse flames, and it's also... like... you drink it. Because it's water. It has meaning to the characters beyond "It is a currency." that a lot of games lack. Currency in games rarely translates to the goods they are traded for, and it's strange comparing it to media where cash sums are relevant because "What are you going to do with all that money?" is, all said and done, a pretty basic character note to hit, and "I want cool sword." just isn't great motivation for gameplay.
And the second is cutting out the middleman - it is labor that creates goods, and in turn, your characters can be smiths, they can be craftspeople, they can be textile workers. And I personally think that having a blacksmith craft a sword from ore - or even better, being the blacksmith that crafts the sword themselves - is more interesting than spending $50 on a Walmart-brand sword. Summon Night: Swordcraft Story (an EXTREMELY underappreciated game) understood this, and making swords in that game is the best, to the point where I'd grind out the janky platforming combat for hours just to make cooler weapons.
At the end of the day, I don't think I have a grand statement to make here. It's just kind of depressing, really. We should be better than putting things in games because they feel like they belong there, because that's just, not how good things are made.