Simple Trade Rules

(Gamemaster's note: these rules are stolen and simplified from GURPS Traveller: Far Trader rulebook)

For simple generation of cargo for Tramp Freighters
Add two world's UWTN together
Subtract 2 if short route (Red Sun to White Sun)
Subtract 3 if long route (Georgia to Red Sun or anywhere to Blue Sun)
Add 0.5 if source world is Ag going to Na or In going to Ni
This is the Bilateral Trade Number
Square the BTN, then multiply that result by Captain or Purser's Intelligence + Influence/Persuasion or Knowledge/Broker to get tons of cargo.

Passengers
Roll 1d3-1 times BTN for total number of passengers.