Nuke the dungeon from orbit
Acquiring a job requires either finding a client via formal means (Computer Use, DC 5-15) via a planet's Datanet, or informal means (Gather Information, DC 15-30) via the local nightlife, cantina-life, or back-alley. Informal jobs can pay better, but can also be much riskier (such as requiring avoiding Legal Entanglements), while formal jobs are a source of low paying guaranteed freight hauling work. Each bulletin advertisement typically will have a comlink code to contact the shipper (some jobs were taken but not taken down, GM's discretion).
Bulletin boards exist in some form or another in most spaceports, and centralizing freight jobs where spacers congregate is only logical. Sometimes for free (or a fee of 5-50 credits) a shipper can post a freight job at a starport for a specific location and target date of arrival. Generally these freight customers are small businesses or individuals who do not have enough cargo to use a bulk freighter service (which is considerably cheaper). Other times the world does not have enough traffic to attract a bulk freighter megacorp.
The number of shipping jobs depends on the population of the system in question, proximity to a hyperlane route (minor or major), and region of space. The following table simulates what jobs are "currently available" in any given system at any particular time. Some of these jobs can remain unfulfilled for days or weeks depending on local traffic.
These modifiers reflect the vital economic activity in Core Worlds versus the Economic Stagnation for most of the Outer Rim. However, there will be more competition where freighter captains frequent, so it is possible that someone else could snatch up all the job postings in a given starport. This is not a problem on worlds like Metellos or Coruscant because the bulletin boards change by the minute. On worlds like Naboo, where the pace of life is longer and there are not many businesses, the bulletin boards change by the week. Another thing for GMs to keep in mind is the size of the community; small thorps on Tatooine will never generate a job, which is why the locals visit Anchor Head or Mos Eisely to find a fast ship that can avoid Imperial entanglements (which is the real trick, and will cost you extra).
Use the following list if the world has no Major Exports or Major Imports. 50% of the time, the cargo being Exported or Imported is exactly what is in the system description. However, there are small manufacturers that operate under a franchise license (or is a knock off) all over the galaxy.
In Republic or Imperial Space, use of the Datanets to fulfill a shipping job comes with a uniform shipping contract, and on worlds with a BoSS office the failure to deliver has almost immediate repercussions (such as suspension or loss of license unless restitution is paid).
Cargo fees are often negotiable. Diplomacy DC 20 to increase cargo fee by 1 credit per ton, DC 30 to increase fee by 2 credits per ton.
Some GMs may want to know if the "normal" job is actually masking the real cargo, such as hiding a narcotics shipment among stuffed animal toys, or shipping brand name items on top of generic knock offs to fool casual inspection. Checking to see if a shipment is legitimate is a GM's call, but 1% of legitimate business could be a front for an illegitimate business. Alternatively, it could also be a sting operation by legal authorities (such as Imperials attempting to map the arms distribution network of the Rebel Alliance by selling arms with a homing beacon aboard the crates).
Passenger fares include normal consumables (food, air, water), and long trips can become costly since a Wookiee or Sludir can consume 3x what a Bith or a Dug might.
There is a 20% chance that the fare is actually a hitcher, willing to provide labor in exchange for passage rather than hard credits.
There is a 10% chance that the passenger(s) are fleeing the law (Sense Motive DC 20). If caught, the price can be negotiated upwards by 50% to 500% depending on the severity of the crime.
For places like Mos Eisely, where the local starport does not bother to maintain a Datanet, the only way to find work is by word of mouth at a Cantina or other public place. Just as likely, desperate freighter captains like Han Solo who need a big score do not bother with bulletin boards, but rather wait around hoping for a smuggling job. Just like Obi-Wan Kenobi and Luke Skywalker negotiated passage off the planet to avoid Imperial Entanglements, the "informal jobs" can turn into more than a freighter captain originally bargained.
The Informal Jobs can use the "Formal Jobs" table results, but there is a higher percentage chance of finding fares who want to go to the same place as the freighter is bound. Many times, a freighter captain will take on several jobs, especially if the location is to the same place or near the same place. While one job might just pay for the fuel and consumables, multiple jobs can pump up a freighter captain's bank account, or it can leave a captain with bartered goods in their hold.
More often than not, freighter captains will hang around for a while until they get a job that is worth their while, and every few days or a week in a starport can change the number of jobs available and the destination. Of course, the really plum jobs are sought after, and it is not unknown for a spacer to sabotage another spacer to pick up a fare or a valuable cargo that is time sensitive.
In other words, no amount of tables can really predict the extreme variance at informal jobs since the strangest people pop out of the duraplast (such as Jedi exiles like Ben Kenobi).