In the struggle to create authentic original worlds, authors need to look at smaller, simpler aspects of worlds and societies to pack as much depth in as few words as possible. Readers and editors are looking for smaller books that still contain full and deep worlds to inhabit. One small aspect that is often over-looked is currency. Currency is something everyone deals with every day, but is given little thought beyond an exchange of value. Currency is a powerful symbol that can tell someone a lot about the society that created it. Let’s look at some popular examples and see what works and what hasn’t.

Star Wars – Credits – The Usual
You may not have even noticed the currency of Star Wars. It’s mentioned only a few times and you could easily replace it with your own national currency and not affect the movie at all. We see Uncle Owen pay the Jawas something for the droids. Luke is given some vague price for his speeder. Eventually Han has a pallet full of something that he’s going to give to Jaba. This is a currency doing the bare minimum of what you want. Our characters are using the currency to give credence to the world. There’s no lengthy explanation of how it works, or the special secret it contains. I give you credits you give me goods and services. The world feels lived in without being overly complicated. The aliens feel a little less alien because a couple credits buys a beer or a bottle of blue booze just like it does here in the real world.

This does evolve a little in the later movies. In Episode 1, Watto, the winged slave owner, refuses to accept Qui-Gon’s Republic credits in the purchase of a new hyperdrive. It’s an interesting exchange because it helps to frame the new world they’ve landed on. One that doesn’t accept their representation of value, and ultimately none of their moral or ethical values as well. It’s a quick exchange but it’s one that anyone that’s traveled internationally can recognize. An easy indication that nothing can be taken for granted.

Star Trek - Credits - The thin veil
The federation credit, first offered for a transaction for goods in the "Trouble with Tribbles" episode, is a currency that only serves to fill a hole. The world of Star Trek is supposed to represent the pinnacle of human society, in so far as Gene Roddenberry could envision it. In the world of Star Trek humans have moved beyond the need for things like money or the greed that comes along with it. This is all fine so long as the Federation remains insular and its citizens have no need to purchase resources or commodities from races that exist outside of it. Now this might have been a simple quirk of world building except that the core idea of Star Trek is a star ship whose main purpose is to leave Federation space and explore the rest of the galaxy and interact with the alien races that aren’t part of the Federation.

It’s a problem found almost immediately by the writers as we see them use the vague invention of the credit to fill this gap. Yet the creator held on to his ideal all the way into the next generation version of the show. During the Deep Space 9 series Latinum or Gold Pressed Latinum was introducted. A physical currency that gave us a look at the limitations the series had been experiencing. Greed is a great motivator, and it gave us episodes with more drama and familiar textures. Heist episodes, battles that have literal cost, and the economic and social impact of command decisions all open up in Deep Space 9 on a human level that the other Trek series could never delve deeply into without involving a stand in race for humans. The stand-ins worked for the most part, but it always felt unnecessary, or at least as unnecessary as the minimalist prosthetics applied to make the actors appear just alien enough to not be part of Federation society. Something that changed eventually as the Deep Space 9 story lines bled back into the next generation and opened them up to human specific conflict within the Federation.

The Stormlight Archive - Spheres - Currency as Commodity
Brandon Sanderson is exacting in his world building, and the currencies he makes are no exception. A Sphere is a bit of gemstone suspended in a crystal sphere. Expose that gemstone to a storm and it's infused with magical power with a handy glow for indication. There are ten kinds of gemstones and each one is subdivided by three denominations. I'll lead you to an excellent break down of all that complexity, but I just want to go over one important aspect of it. Spheres are more than just weird money. They also serve as a visual representation of the society that uses it, and eventually as a source of magical power for the story's protagonist. The gemstone itself is the real currency of the society but it's the infusion of power that makes it a commodity.

Kaladin, one of the POV characters, finds that he can use the infused gems to increase his power, but as a slave he has very little access to money and, as a consequence, only small amounts of magical power. As his position changes through the series and he has more access to additional currency, his power increases. The spheres have a visual component as well, which is used to great effect as the characters move in and out of different class divisions. Rich people essentially illuminate their homes with thousand dollar bills handing on the wall while lesser homes use smaller denominations or candles for the truly poor. It's a small thing but it weaves itself through the societies and magic systems that give extra little details to make the world real and the people living in it believable.

If it has one flaw it’s in its complexity. The difference between the denominations and the gemstone types make the economy and magical ramifications confusing, making the system difficult for anyone not interested in reading through the wiki. Ultimately the complexity doesn’t add anything to the story as the relevant parts of the currency are all the basic components. There are only two books in this ten book series released, so there’s still time to pay off the more complex aspects of Spheres.

Buffy the Vampire Slayer - Kittens - Funny Money
First introduced in the episode Life Serial we see demons using live Kittens as chips in a backroom poker game. An especially humorous moment that at once secures the audience against the demon side, because it's unlikely those kittens were going to be put to good purpose at the end of the game, and contributes to the surrealist nature of the episode that sees the slayer struggling to re-enter the normal world after a bout of being dead.
In later episodes and seasons it becomes a running gag.

It's a nice flavor for the underworld that really only gets peaked at in series, but it's never handled the same way twice. The lack of a clear and developed system is often part of the joke, leaving the viewer to wonder if they heard correctly that kittens may lose their value when they cross the line to cat. Sometimes the demons are shown to be trying to blend with human society, but other times they exist with their own demon bars and communities. The kitten currency could have been a nice way to cement some of that lore in a more substantial way.

This is also a currency that you eat. (I assume they are eating them anyway, because you know…evil.) It's something like winning a poker game and then stuffing your face with the chips. Problematic obviously if you are looking to make a nest egg. Though since your money can also go bad, grow old that is, eating it might be a nice solution.

John Wick - Coins – Currency beyond money
This is my favorite because it’s executed subtly yet holds so many great aspects of the world in its application. In the film John Wick, the eponymous protagonist is forced to re-enter a world of crime and murder he left behind for his recently deceased wife. There's also a puppy but let’s not talk about that or I'll start crying. In the process of getting the things he needs, guns and what have you, he also acquires his collection of gold coins. The coins are then used as a representation of some kind of favor system within the underworld.

Wick uses it to buy room and board, bribe goons, and ensure the neutrality of his chosen safe house. It’s not shown who is providing the value of the coins, whether it's John himself or some higher authority, they are instantly recognized and serve as a catalyzing force to cement John's place within the underground system. It's a fascinating currency because of the nature of its use and the implication of its source.

A currency that gives one power within the underworld and yet at the same time obligating the user and the recipient to that system. Since the gold coins are not upheld by anything similar to a national monetary fund or credit rating, it’s only in the continued functioning of the underworld system that the coins hold any value. It's a great expression of John's own struggle that even as he uses the value of the coins to his advantage, he's tearing down the system that gives them that value.

Currency and Worldbuilding