Star Wars: Birth of the Republic
You buy a bunch of commodities as your stake (we don’t care what kind of commodities they are, though, only their value in credits), and then roll Knowledge (Bureaucracy), because that’s the closest thing to a Knowledge (Commerce) skill in this system. If your result is 15-19, you break even exactly. For 10-14 you take a 25% loss, at 5-9 it’s 50%, and at 1-4 it’s 75%. 20-24 it’s a 25% profit, 25-29 it’s a 50% profit, and so on. This means if you’re level 1 with either a training or a really good INT, you should be breaking even. With both, or a higher level, or a skill focus, you’ll make a profit. This assumes a normal crew (and their wages are folded into the profits and losses). If you have a Skilled crew, you get a +1 bonus but must pay them 3k to run the ship. If you’re Expert, you get a +3 bonus but must pay them 6k. At Ace, you get a +6 bonus but must pay them 15k.
If you want to run a high-risk route (either because there’s pirates or something or because you’re smuggling), then you break even on a 20-24. On a 15-19, it’s a 50% loss, and on a 10-14, you lose your entire stake because you had to ditch the cargo. On a 9 or lower, you lose the cargo and your ship (not to mention your crew, which has no mechanical effect but which might make you feel bad). On a 25-29, you make a 50% profit, and on a 30-34, you make a 100% profit, and so on. If you can regularly manage a 30+ (so if your total bonus, including INT, training/focus, and crew is at least +20), high-risk routes are more profitable.
Finally, there’s the maximum stake for a route, and your competitors. The more backwater a route is, the fewer competitors you have, and thus the easier it is to gain a lucrative trade monopoly. However, the more backwater the route is, the lower the maximum amount of credits you can stake. If there’s only a thousand people on the colony you’re headed to, it doesn’t matter if you can afford a million speeders, because there just aren’t enough buyers. A Backwater route has a maximum stake of 25k and the local competitors have a +5 bonus. A Colonial route has a maximum stake of 100k and the local competitors have a +10 bonus. A Core route has a maximum stake of 250k and the local competitors have a +15 bonus. Finally, the Trade Spine (which runs from Duro through Corellia, Kuat, and Coruscant out to the Perlemian worlds) has a maximum stake of 1 million credits and the local competitors have a +20 bonus. Each route also has a minimum stake equal to half the maximum stake of the previous route (Colonial has 12.5k, Core has 50k, etc. etc.). The minimums and maximums are both double if you’re running a high-risk route. If you’ve never run the route before, you take a -2 penalty to it, and this includes moving from a normal route to a high-risk route of the same type (i.e. a normal Colonial route and a high-risk Colonial route are different routes).
Competitors don’t matter so long as you’re just running normal goods, but if you want to make obnoxious amounts of money you can try and get a trade monopoly, in which case you have to run your competitors out of business. In order to do this, you must pay five times the maximum stake for the route and then roll your Bureaucracy against your competitors’. If you succeed, from then on all profits on the route are doubled and all losses are halved. If you move your crew from a trade route you have a monopoly on to another trade route, however, you will abandon the monopoly and must pay and roll again to get it back.You can, however, move a crew off of a monopoly route and put another crew on that route at the same time in order to preserve the monopoly.
You need to have purchased a different freighter for each route. One freighter can’t run two different routes at the same time. Likewise, you need a different crew for each route. If you want the Ace bonus on two routes, you have to pay two crews. If you get a lot of different routes, you can make one roll for all of them instead of rolling each one separately if you like. Just total up your total stake, roll, and multiply. You will have to roll your normal and high-risk routes separately though, as they have different DCs.