In D&D, there is a global economy shared by all nations with a unified currency of standard value based on (and for one coin, made of) gold. The coins are of standard size, weight, and value in all nations, with minting being used as a way of devaluing the economies of other nations while overvaluing your own, through the prejudice of salespeople alone.
The weirdness of all this got me thinking. At first, I was just concerned with how such a system was formed and sustained. That was solved fast: in my settings, dwarves invented the first currency based economy and basically forced everyone else to use it in order to trade with them at all. The mountainhomes are all connected by the deep roads, linking dwarves settlements and ruins around the globe. Because everyone has to trade with dwarves, everyone is making the same currency, so they might as well use it with each other too. While nations use minting of coins to engage in economic warfare, dwarves wouldnt give a crap, gold is gold, and if you shape youre coins right, they are symbolically worth it. If you don't want one of the coins they use in a deal with you because it has an enemy's mark on it, they're happy to squash it smooth for you. Simple done. The dwarves are basically the hub of the global economy. It does not exist naturally, and is sustained by their arrogance and stubbornness alone.
But then I started to wonder. Imagine, for a second, that we used the Gygaxian currency, based on fractions of gold weight, in our modern society? How would the prices of things look?
Right Now, a pound of gold is worth 19,892.8 USD. Let's call that 20,000$.
A gold piece is worth its weight in gold, literally: 0.1lb, which comes out to 2,000$. Holy shit. If you're paying for something in gold pieces, that ain't no joke!
Silver pieces are worth 1/10th of the value of a gold coin, so they have the same value as 1/100th of a pound of gold, or 200$
And, if you haven't seen the pattern, a copper piece comes to 20$.
Oh, and platinum pieces, representing 10 gold pieces, would have the same value as a 1lb gold bar- 20,000$ worth of stuff. If you're paying in platinum pieces, you're making one of those major life purchases, like the down-payment on a house, or a brand new sports car.
Wowzers. The world would certainly be strange! For one thing, we almost certainly would have either expanded the coin range, or reduced the weight value of the non-gold coins. We would need coins to represent 1/10,000th and 1/100,000th the value of a 1lb gold bar, otherwise our economy would be outrageously inefficient due to value loss on lower value items!
But D&D isn't modern, it's medieval. And 5th edition is dark-ages, with technology and global populations matching the time just after Justinian's plague cut the world population in half. Let's see what some of those items are worth relative to what we value a pound of gold in reality...
Shortsword: 20,000$ (Same price as a shield)
Plate Armor: 3,000,000$
Shortbow: 50,000$ (that is also the value of a BOOK.)
A bundle of 20 arrows is worth 1gp, or 2,000$, so that works out to 100$ an arrow.
A mine's pick is 4,000$.
An ink pen is 40$! A single vial of ink to write with it will run you the same cost as a sword or shield!
A flask of oil comes to 200$.
A magnifying glass is worth a staggering 2,000,000$!!!!
Bagpipes cost 60,000$.
Riding horses are 150,000$, and a warhorse comes to 800,000$.
The most expensive item in the PHB, a galley, comes to 60,000,000$.
But all is not lost! The people are also paid in this currency! What kinds of wages would we have?
People in D&D get paid a daily wage, not an hourly one. There are two standards of pay, aside from bounties: unskilled and skilled. Unskilled is anything you need no external training for. Burger flippers, delivery boys, shelf stockers, cashiers, general laborers, etc. Skilled is anything you need special training for, including what we would call professionals, so that would be lawyers, soldiers, doctors, police, bankers, geneticists, barber's, taxi drivers, welders, etc. Anything that demands a license or certificate.
So, entry-level teens get 2 silvers a day, or 400$. That's 32$ an hour, guaranteed, every day they work.
Professionals? They get 4,000$ a day. They get paid 500$ per hour.
A modest lifestyle costs you 2000$ a day, so unskilled workers will still be living in cramped apartments with multiple room mates. However, if you manage to get hold of a professional license, you literally have a golden ticket to permanent comfort and economic safety. Saving 1000$ a day, you could buy a riding horse in about 5 months. That's the medieval equivalent of getting a car- a car you can breed with other cars to get new cars for free- a car you can eat if the winter gets too cold and you run out of food. That's not bad!
So, what would it take for someone to become an adventurer? I'm going to say a sword and shield are all that is required, bare minimum. At 40,000$, a professional of any stripe can afford to become an adventurer after a little more than a month. Unskilled workers, if they lived a truly crummy lifestyle while saving, could do it in half a year.
On the other hand, the least you could pay for a burger is 20$.