So, now that I’ve been on a couple economic adventures, the math and ramifications thereof are becoming clearer to me.
Maximum profit I can make is a function that looks like QPT(Y-X)-C where Y is the percentage sale price, X is the percentage purchase price, T is percent remaining after tax, P is the actual price of the goods, Q is number of loads, and C is flat costs like wagons and henches. So, what’s interesting to me about looking at it like this is that it produces a string of things that I want to be very high or very low, and trying to minmax one of these things has consequences on the others.
For example, the obvious choice is to maximize Y, because selling at a high price is good. Because prices are the same for all merchants in a market, if we don’t like our Y, we have to move. Larger markets have 10% higher prices, but are also generally far apart. Smaller markets are an option, but limited merchants and loads means we risk not being able to sell our entire package- an upper limit on Q. Plus, if we go really small, there’s a 10% price drop! So trying to get the best price for the goods you’re selling is actually kinda tricky.
Now then, the next logical choice is to think about X, because buying cheap is good too. Because we haven’t bought a good yet, every good is a potential purchase. Thus, if Bigby’s rivals hadn’t died before completing their research, casting Detect Invisible Hand would give you 30 options for X. (Note: I’m taking Mathmatical Statistics II right now, and I briefly considered actually doing the math to find out what the density formula for lowest number of 30 normally distributed rolls would look like, but I really can’t be bothered.) Hopefully, out of 30 4d4 rolls, you’d get a 4 somewhere, right? Of course, you can’t actually know all 30 prices. In fact, you usually actually only get like six merchants your first week (and what party ever wants to spend more than a week in town?) and then you can spend a reaction roll to convince each of them to tell you about a second good, so if we were really serious about minimizing X, it’d be more like the lowest of 12 rolls.
This brings us to our next issue: Because we can’t ask a merchant about more than two goods (The one he arrives with and the one we convince him to deal in) there’s a fundamental link: The lower X goes, the lower Q goes. Thus, maybe we find out that grain is selling at 10% of normal price because the city is flooded with grain right now, but the guy selling the grain only has four loads. (Which, for reference, is 80 bags of grain for 4 gold, so if nothing else you should buy it and tell him to send it to the last starving village you visited, hero.) This also brings me to a related note about the difference between X and Y: If your DM treats bargaining as additive, it gets really, really good for small numbers. If you can go from 30% to 20%- Hurray for your “10%” actually slashing off a third of the price! (Or go back to that poor grain merchant and see if you can’t persuade him to just give you the grain so he can clear out his warehouses and buy something worth his time; and besides, it’s all going to that starving village.)
So, moving right along, let’s talk about Quantity and Price real quick. The obvious relationship between these two is that your adventurer has limited money, so the higher the base price, the fewer goods he can buy. Thus, 2000 gold is either two crates of opals or ten crates of tools.
What’s interesting about this relationship is that Quantity is limited by market forces, whereas Price is the player’s choice. Thus, if I’ve got 2000 gold to spend, I can walk up to the poor sod with his 80 bags of grain and buy all of it and had 1996 gold gathering dust, or I can try to convince him to deal in, say, elephants, knowing that even if elephants are like steeply discounted, I still won’t have to buy very many before I’ve hit my 2000 gold limit. So as it turns out, Quantity is almost irrelevant because we can control base Price so well.
But wait, a few long, long paragraphs ago, we found out that the main downside to minimizing X (Purchase Percentage) was that it cost us in lowered Q! But we just found out we give a near-zero quantity of excrement with regard to Q if P is sufficiently high! Thus, my conclusion is that the optimal strategy for merchanting is to investigate a large number of high priced goods (for whatever definition of high priced your adventurer is using right now; a level 3 adventurer will probably be able to max his venturecard on tools or glass, while an 8th level adventurer will pretty much only care about gems and silk), then purchase the one with the largest discount.
I’d say that a sustainable business model based on buying precious goods at a fraction of their worth is a silly artifact of poor rules design, but that’d be really rude to Alex, particularly because for the past three years I’ve driven past a Cash 4 Gold on the way to work so I have to admit that the rules seem to model reality well. I guess the only thing to do now is to start the party’s low-level henches on learning to twirl signs.
