Trade in a medieval setting

[Six]

So, one of my players in a game I'm starting up has acquired some land, and I anticipate that trade and economics will become very vital. However, as we all know, DnD's money system sucks. I was wondering if anyone had really good trade oriented systems i could use, or suggestions for a way to construct a spread sheet (E.G 1 unit of iron=1 ton, and 1 unit iron is worth X units of products Y, Z units of product A, etc) and any suggestions on what kinds of ranges would make sense taking into account medieval economics, as I want to give a realistic representation of trade.

[Brother Oni]

For simplification, stick to a equivalent monetary value system, based off the D&D one.
Messing around with a barter system (which is what your 1 unit of iron = x products of y is) becomes very complex and very individualised - taking a medieval example, sea fish wouldn't be worth much to someone living in a coastal region, but would fetch you a pretty penny when salted/smoked and transported a few hundred miles inland (to the point that only the nobility and rich could afford to eat it).

If you want to make it more complex, have regional variances based on location (coastal/inland), season (fresh fruit is worth less in the summer), adverse effects (grain is worth more if the harvest is poor) or culture (historically, western medieval societies had a big thing for spices), but this all depends on your campaign world.

[Gourtox]

This seems like it belongs more in roleplaying games section.

[bebosteveo]

I can't help much with exchange rates. In a pinch, I'd say make a rough estimate of the number of man-hours needed to acquire a particular good as use that as its "inherit value". Then eyeball that number up or down based on rarity or supply/demand or whatnot. Like Oni said, for simplicity you'll want to value everything on one metric (even if the players never see it) then fluff it up from there.

As far as volumes are concerned, it depends on how its transported. I know that cogs and galleys could carry a few hundred tons without issue and land caravans were limited by how many animals you had to load with goods and could care for. Since trading ventures were usually long, expensive voyages to distant lands, you can be sure that they filled every bit of their carrying capacity to maximize returns. Buying/selling 10 tons of silk or 50 tons of salt/spices in one transaction would probably be fairly ordinary.

Even if you aren't using the system, I'd look into the GURPS supplements. They tend to be known for putting mechanics behind this sort of situation without being GURPS-specific. A quick look over their list shows that you may want to consider Low-Tech or the Low-Tech Companion 3 (with strong preference towards the later), though I have not read either one and can't comment on content.

[Gwyn chan 'r Gwyll]

I'd personally just wing it.

It's that, or take some first-year university Economics courses, and derive an epic 400-page system to model medieval economics.

[tigerusthegreat]

How in depth do you want to go?

Simple: Make a list of a group of general items (food, stone, minerals, wood, weapons, armor, horses, livestock, etc), assign them a value per "unit" (can be totally arbitrary). Decide what of these items your land makes as a base value, then modify this based on what happens in the game.

Example: I decide the following values for a unit of these items:
Food: 10gp
stone: 15gp
Minerals: 50gp
wood: 35gp
Weapons: 100gp
Armor: 125gp
horses: 70gp
livestock: 90gp

I decide my player's land is very fertile, but poor in minerals, wood, and exploitable stone. So I decide it has a base production of:
Food: 10 units
Stone: 1 unit
Minerals: 0 unit
Wood: 2 units
Weapons: 0 units
Armor: 0 units
horses: 5 units
Livestock: 15 units

This land's base production, based off of my assigned values is (100 + 15 + 70 + 350 + 1350) 1885 gp. Give your player an option how to tax it, and they generate that revenue.

With this system, you can keep things relatively simple once you decide the base values, or you could make it exceedingly complex. On the simple side, say there's a war, well that increases the value of food by 50%. Drought? drops production by half. Your player invests gold into exploring his territory for mineral wealth? give a chance to increase the base production of minerals. Your mind is the limit here. You can make this production list as long or short as you like.



Now, say you want something much more complex, or have multiple players involved. You use a similar system, but your base values are modified by supply and demand. Decide whether an item is a primary product or a secondary product, primary being items produced without using other trade items, and secondary being produced by using up primary items. For example, grain is typically a primary product, but weapons, which use wood and minerals in their construction, is a secondary.

Primary products do not add to the demand of any other items. Secondary products, however, add to the demand for primary items. Say you decide that every unit of weapons needs 1 unit of minerals and 1 unit of wood. Every unit of weapons produced in any territory increases demand for minerals and wood by 1 unit each.

Working supply and demand into the equation; if supply > demand, then the value of products goes down, but if supply < demand, the value of products goes up. adjust accordingly.

That is probably way to complex for a tabletop game, though. If you want to see a super complex system in action, look up Europa Universalis's economic system. It is crazy.

[Gwyn chan 'r Gwyll]

Nah, Europa Universalis' system is actually quite simple.

Victoria 2, on the other hand... now THAT'S one helluva economic system model!

[Aux-Ash]

My rule of thumb is: decide what a single day's worth of meals for a household is.
Then go from there.

If it takes 12 days to produce something, then the price will be minimum 12 days worth of food plus material costs.

Materials costs are the combined cost of production and transportation. It's bought for... ex. 12 days worth of food, then transported for 2 months. Then the price is going to be 72 days worth of food. Minimum. Then add costs for guards (calculated in the daily expense of guards) guides and skill.

Throw some profit on top of it all. And voila, a logical price.

[Xyk]

I suggest they hire an assistant to do all that while they go on wild adventures. Just assume they get some sort of randomly assigned profit or loss.

Depending on how much they pay their assistant, it could be something like profit= -10,000gp + 1d20(1000gp) or it could be profit= -5,000gp + 1d20(1000gp). D&D is not a good macro system, it's really best to play with a party of heroes dispatching foes or solving mysteries or something of that nature.

[LibraryOgre]

First of all, you might go looking for the old Birthright setting, and look at their trade rules. Trade was based on Gold Bars of value, and part of a large domain-running system.

http://www.birthright.net/ May have some resources towards that, especially designed for d20 (as that's pretty much Common around here).

That said, you may also wish to look at the level of abstraction you want. I've got an article I worked up for HackMaster that covers investing by PCs, and running their own businesses, mostly based off simple die rolls and a handful of modifiers... put in X money in investment income, you get Y% back. If Y<100, you lost money. It's good for just straight-up roll-and-ignore investment.