The default currency of the world is the copper piece, also known as a copper bit, or a bit of copper. The slang for copper is simply “bit”, just as the slang for dollar is “buck”. Embracing this system is key for understanding and engaging with the world.

Many other game systems, TTRPGs or VRPGs, use gold as the default currency, which can be difficult for players to adapt from. To many people, 1gp = $1, which simply doesn’t make sense in a D&D campaign that uses copper, silver, and gold. To make the transition easier, it helps to embrace the cp -> $ conversion where 1cp = $1, 1sp = $10, and 1gp = $100. It’s not perfect, and the currencies shouldn’t be tied exactly to one another, but it is an easy guideline to help players understand. Below are listed some basic things that can be bought in both a game world and the real world. Items that don't convert well have been avoided, like salt and pepper which are abundant and cheap today but used to be exotic and expensive.

10 1 day of meals (poor) 15
30 1 day of meals (common) 30
50 1 day of meals (good) 60
20 Ale (gallon) 27
5 1 bowl of soup 5-6
10 Hat 15-20
30 Leather belt 30
50 Iron Pot 40+
20 1lb of butter 5-6
200 Adventuring Pack 100-500
200 Dagger 100+*

*You can find hunting knives for less, but if you're going to buy something quality instead of factory made in china you'll be looking around the $100 range.

This way, when you buy an arming sword for 1,500cp, you have a better connection to the value of your weapon. 15GP is pretty abstract and seems like chump change, but that arming sword takes a smith, a relatively well paid individual, a full 10 days to make. If they take weekends off, that’s 2 weeks of work for them.

In our modern world, we don’t use $100 as the base. A room at a motel doesn’t cost “half a Benjamin” although, you could phrase it that way if you wanted, it costs “fifty dollars” or “fifty bucks”. Similarly, a night at an inn doesn’t cost .3gp, or 3sp, it costs 30cp. Copper is the base currency.

In Arcadia, there are 4 common coins: Copper, Silver, Iron, and Gold. 1sp = 10cp. 1ip = 25cp. 1gp = 100cp. Iron and Steel are interchangeable in the same way that copper, brass, and bronze are interchangeable. It’s not perfectly sensible, but it makes things run more smoothly. Additionally there are the rarer platinum and mithril coins, worth 200 and 2000 bits respectively. All coins are 50 to the pound, which means each type of coin is sized differently as they all have different densities. Mithril > Iron > Copper > Silver > Gold > Platinum. This makes it easy to tell coins apart if you can’t see them, and makes it easy to determine the weight of your wealth. It also helps us understand how many coins we need if we’re going to melt them down and turn them into a good. Need 11.2lb of mithril for that suit of mithril chain mail? That’s (11.2 x 50) 560 mithril coins you’ll need to supply your smith with (in addition to their wages).