In their youth, adventurers are wont to squander their treasures. But older, wiser adventurers, who have faced death one time too often for a bare handful of coin, may find that their favorite type of venture is mercantile.

The riskiest, but most lucrative, form of mercantile trade is arbitrage: The movement of goods across long distances from markets where they are cheap to markets where they are expensive. Arbitrage traders must identify an opportunity, front the cost of purchasing large quantities of merchandise, safely transport it across long distances to distant markets by ship, and then find a buyer willing to pay enough of a premium to earn the trader a profit. Because it requires large sums of treasure and risky travel across the wilderness, arbitrage is a common choice for merchant-adventurers. Follow the steps below to adjudicate arbitrage trading.

In order to buy and sell goods, the adventurer must first travel to a market. A market can be anything from a humble county fair to a city-state's outdoor bazaar to the ports of a major metropolis, but each has different characteristics. Each domain (as described under Strongholds and Domains) generally has its own separate market. Markets are rated by market class from I to VI, which rate their size and importance. The vast mercantile hubs of empires, with urban populations of 20,000 families or more, constitute Class I. Major ports, national capitals, and other large cities of 5,000 or more families constitute Class II. Provincial capitals and medium-sized cities of 1,750 to 5,000 families make up Class III. Small cities and large towns of 600 to 1,750 families make up Class IV. Small towns and large villages of 250 to 600 families are Class V. Any village of 250 families or less is Class VI.

Each market will have a unique set of demand modifiers, determined by the Judge, for different types of merchandise. The demand modifier modifies the availability and price for merchandise in the market. A low demand modifier indicates that there is a surplus of that type of merchandise available, usually because the market is a producer of that merchandise. A high demand modifier indicates that the merchandise is hard to get and very expensive.

Example: The border capital of a rural Southern kingdom is a Class III market. Its demand modifiers are: Common Wood -2, Hides -2, Common Metals -2, Ivory -2, Rare Furs -2, Gems -2, Grain +1, Pottery +1, Dye +2, Cloth +1, Glassware +1, Tools +2, Armor +2, Spices +1, Silk +1. This capital is a great place to buy timber, furs and hides, ivory, and gems, and a good place to sell dyes, tools, armor, spices, silk, and similar manufactured or luxury goods.

Each time adventurers enter a market to buy or sell goods, they must pay a toll (unless they sneak in). The cost of the toll is listed below on the Market and Merchant Table. For characters entering to sell, the minimum toll is always 1 dinar per load. This represents harbor fees paid to the harbormaster of a port, guild tolls at the city gate for caravans, etc.

Once a market is selected, roll on the Merchants column of the Market and Merchant table below to find the number of merchants interested in transactions with the adventurers. For each merchant, roll on the Loads of Merchandise column to determine the volume of goods each merchant can handle. A "load" is a generic unit - the exact nature of a load varies depending on the merchandise (see the Common Merchandise and Precious Merchandise Tables, below).

If the adventurers are buying, the Loads of Merchandise result shows how many loads the adventurers can purchase from that merchant. If the adventurers are selling, the Loads of Merchandise result shows many of their loads that merchant will be willing to purchase from them.

One half of the merchants (rounded up) become interested in transactions within the first week the adventurers enter the market. One quarter of the merchants (rounded down, minimum 1) become interested during the second week. The remainder of the merchants will become interested in transactions in the third week. Additional efforts to locate more merchants in the market may be made at the end of this time, but the dice roll takes a modifier of -2 for each week that the adventurers have been in the market.

Example: Abu leads a caravan into a Class III market. There are 7 merchants available. 4 merchants express interest in doing business in the first week his caravan is in town. 2 more merchants become interested in doing business in the second week. The last merchant becomes interested in the third week. As this is a class III market, each of these merchants will buy up to 3d4 loads of merchandise.

As long as they have a caravan or vessel at a market, adventurers will have to pay moorage or stabling fees. Moorage fees for ships are 1 dinar per 10 structural hit points per day. Stabling fees are 2 dirham per mule, 5 dirham per horse, 1 dinar per cart, and 2 dinars per wagon per day. For instance, a merchant with 2 wagons drawn by 4 horses each will have to pay 6 dinars per day.

An adventurer buying and selling in a domain he controls (see Strongholds and Domains, above) always has access to the maximum number of merchants available, and need not pay moorage, stabling fees, or tolls.

Once the nature of a load of merchandise has been determined, its market price must be calculated. Each type of merchandise has a base price which represents an average value of the commodity given its utility and scarcity. The base price is then adjusted for the economic and political factors of the market where the transaction is occurring. These factors are modeled randomly using die rolls and situational adjustments.

The market price is the prevailing price for that market, and should only be calculated once for each type of merchandise for each visit to the market. Different merchants in the same market will not buy and sell the same type of goods at different prices.

To determine market price:

• Find the merchandise's base price on the Common or Precious Merchandise Table.
• Roll 4d4. Add the demand modifier, if any, for this type of merchandise in this market. Add 1 if the market is a Class I or Class II. Subtract 1 if the market is Class V or VI. Modify by 1 in the adventurer's favor if he has a monopoly in that type of merchandise. The Judge may apply any special modifiers (from war, calamity, etc.) he deems appropriate.
• Multiply the result by 10 and apply it as a percentage of the base price. This is the market price for the merchandise.

Example: Having lined up some interested merchants, Abu sells his dyes and pigments. The base price for dyes and pigments is 250 dinars. Rolling 4d4, and adding the +2 from the demand modifier since the city is a major consumer of dyes and pigments, Abu scores an 11. Dyes and pigments in the city have a market price of (11x10) 110% of the base price, or 275 dinars per load. Abu's 20 loads of dyes and pigments are worth 5,500 dinars.

The market price is calculated once when merchandise is bought, and again when it is sold in a different market. If the adventurers wait in the same market hoping for the price to change, there will be a 10% cumulative chance of a price change (re-roll) for each type of merchandise each month.

If the adventurers find a merchant buying or selling merchandise at a market price acceptable to the adventurers, a transaction may occur. Adventurers may transact with any or all available merchants, but each merchant will never buy or sell more than the number of loads rolled for that merchant in step 2.

When adventurers buy goods, they must pay a labor fee to cover the cost of loading the goods onto their ship or caravan. When they sell goods at their destination, they must pay another labor fee to unload the goods. The labor fee is 1 dinar per 200 stone of merchandise. Adventurers selling goods will also have to pay a customs duty equal to 2d10% of their market price. Player characters disinclined to pay such fees can, of course, attempt to smuggle goods into the market.

Example: 20 loads of dyes and pigments weigh 500 stone, so Abu's labor fees will be 3 dinars. The city has an 11% customs duty, so Abu will have to pay a fee of 605 dinars when he sells his goods for 5,500 dinars.

If the adventurers have purchased merchandise, they will need to transport their goods to a new market for sale. When the adventurers reach a new market, they may sell their merchandise, starting with step 1, above.

If an adventurer is operating a vessel or caravan, he may transport passengers between markets. The number of passengers available is determined on the Passengers and Shipping Contracts table. Roll on a 1d20 to determine the destination of each passenger. On 19+, the passenger wants to hire a caravan or vessel to travel to a distant market of his choice, 2d20 x 100 miles away. Otherwise, the passenger simply wants to be transported to the closest market within one size class along the way towards the adventurer's destination.

Passengers will not accept transport from adventurers they deem untrustworthy.

Each passenger counts as 200 stone of cargo, not including any food or water required for their passage. The standard fee for passengers is 20 dinars per 500 miles by sea or 20 dinars per 150 miles by road (rounded up). However, passengers that hire a vessel or caravan to go to a particular designation must pay as if they shipped enough to fill the cargo hold. This fee is 1 dinar per 10 stone of cargo space per 500 miles of distance by sea or 1 dinar per 10 stone per 150 miles by road. A round-trip fee may be charged if the destination is at least 2 market classes smaller than the originating market. Passengers will generally pay half in advance and the remainder upon safely reaching their destination.

An adventurer operating a vessel or caravan may also solicit shipping contracts to move cargo for other merchants. The number and size of the shipping contracts available is determined on the Passengers and Shipping Contracts Table. The destination of shipping contracts is determined as per passengers, above. Like passengers, shippers will not accept transport from adventures they deem untrustworthy. A Reaction Roll of 9+ is required to secure each shipping contract.

A shipping contract pays 1 dinar per 10 stone of cargo space per 500 miles by sea or 1 dinar per 10 stone of cargo per 150 miles by road (rounded up). Shippers will not generally disclose the merchandise they are shipping. The Judge may roll on the Common Merchandise table to determine the precise weight of the cargo to be shipped, or simply assume it is a mixed shipment weighing 70 stone per load. Adventurers will be expected to offer free passage for one merchant representative who takes care of the goods and tax payments. Shippers will generally pay half in advance and the remainder (through an agent) upon their cargo safely reaching its destination.

Characters may both accept passengers and shipping contracts and buy their own merchandise to fill out cargo space. As with merchants, one half of the passengers and shipping contracts (rounded up) become interested in a transaction during the first week the adventurers enter the market. One quarter (rounded down, minimum 1) become interested during the second week. The remainder becomes interested in transactions in the third week.

Use the following table to quickly determine the costs, profits, or treasure of merchant ships or caravans. The table values were determined based on the average values for number of passengers, shipping contracts, merchants, and merchandise given in these rules. Large sailing ships and huge 30-40 wagon caravans are assumed to ply trade routes between Class I and II markets, while small sailing ships and caravans ply the secondary trade routes between Class II and III markets.

*Roll on the wandering monster table for the region to determine specific monster. Each monster's parts have a dinar value equal to the monster's XP value$

Note: When quickly calculating average hauls, merchandise has an average base price of 300 dinars and an encumbrance of 70 stone per load. Common merchandise averages 180 dinars and 80 stone per load. Precious merchandise averages 1,000 dinars and 10 stone per load.

Why are they so complicated T_T

I removed some parts already.
We can put them back in later if we want to.
But I like rules that are much simpler.

Even this is pretty compliated, but it's a start:

Just: price: (4d4+mod)×10 percent of base price.
There is a price reroll every 1d10 months.
For a market I, you can buy/sell ((d6+2)×6)d8 loads.
For a market II, you can buy/sell (d4×4)d6 loads.
For smaller markets we'll extrapolate from the above rules.