Welcome to the new age of credits on your local branch of Space Station 13. Credits, Holocredits, Cash, Coins, you name it, all of them function as money on-station, and can be used to buy products either through the cargo department, your local vending options on station, or through good old fashion bartering for goods and services.
Making Cash
At the start of your shift, you begin with a set number of credits, based on the relative difficulty and hazard of your job, as listed in the table below. Your round-start funds are a passive pool of money that you have to buy things from vendors, as well as to trade between your fellow crew members. However, there are several ways to bring in additional money outside of your starting pool:
Payday
Every 5 minutes, crew will receive a new paycheck, which is automatically added to your account. Regular jobs are given 50 credits, while lower paying jobs that are non-critical to the station's function receive 25 credits. Additionally, your stating credits are higher if you are playing a head of staff position, and lower if you play a non-critical job.
Exporting price tagged goods.
You can use a (blue) universal tagger (Not the green universal tagger, that's used for custom vending machines!) to give yourself a portion of the sale of any given export. Scan the sales tagger with your ID card, then alt-click to adjust the amount of profit you're asking from the sale, up to a maximum of 50%. However, higher splits may result in cargo just taking your exportable goods for themselves if they're deplorable scum it turns out to be too much work. Once sent off on the cargo shuttle, a portion of the profit is sent to your account tied to the ID you swiped.
Most every job at least has some kind of exportable products tied to them, like food, stock parts, machines, etc. If you're unsure if it can be exported however, then you can use an export scanner to see its base value when sold.
You can also use a tablet to print out barcodes for the same purpose.
Civilian bounties
Collect items for cargo to export! Your ID will be given a bounty task, and upon completion, you will receive a bounty cube. Bounty cubes, when sold, will give the cargo department a healthy chunk of credits, and you'll be given a 10% cut. Your bounty selection may vary based on your job, but if you don't like a bounty you take or just can't manage to find the items, you can always change your bounty five minutes after accepting it.
Five stars, chef
Bartenders and chefs can use seating indicators and the handy-dandy robot restaurant portal to teleport in robot customers - paying customers - who will give good money in exchange for specific food or drinks. Chefs can satisfy a customer with the requested food item, while bartenders can satisfy customers with 10u of the requested drink. This can be a quick way to rack up money.
Striking It rich
Turning in raw ore into an Ore Redemption machine allows crew to then claim mining points, as a reward for their hard work. At a mining vendor, mining points can be exchanged for many different goods - including some good old-fashioned moolah. As an aside, sheets of processed ore can sell for a fortune, especially the more sought-after ones such as solid plasma or diamonds.
(Brief)cases of making cash.
Syndicate agents - or anyone with an unlocked syndicate uplink - can purchase a briefcase full of cash for 3 telecrystals, raking in a whopping 5000 credits. You can buy a LOT with that kind of money, as long as no particularly observant cargo techs or quartermasters notice you simply haven't done that many bounties. (Though you could always slip them a portion to keep quiet...) Additionally, a CRAB-17 device can be purchased for 7 telecrystals, which anonymously siphons all of the crew's money to you over time, as long as they don't get to the machine it creates to save their credits.
Something's seedy.
Botanists have a unique source of income available - Centcom is willing to pay for mutated seeds! As long as you make sure to use a sales tagger (described earlier,) you can ship off all sorts of rare and strange specimens you've grown and get rewarded for it.
Treasure Hunting
For the more adventurous types, the ruins scattering space house a great deal of loot, including cold, hard cash. If you don't mind the dangers posed by the final frontier, exploration is a fast way to make bank. In addition to regular money, you can also sell lavaland relics and weapons for a nice payday.
Scam your coworkers!
Don't forget this is a multiplayer game, and there are plenty of crewmates out there who likely need their money less than you do. Trading, burglary, or just asking nicely can all net you credits very easily, and tapping into an untapped market can really let you rake in the dough. Just remember not to break any of the server rules.
Good methods of being able to obtain credits from buying and selling goods or services include the bounty board function on Newscasters. These can be located all throughout the station, and let you pay applicants after completing a job.
Vend-a-Trays are unique machines that the chef and bartender start out with at roundstart, that allow you to insert food for sale, and you automatically receive the profit after someone buys it.
Lastly, Custom Vending Machines refills and boards can be made from the autolathe and protolathe, that allows you to supply a full vending machine worth of items, and can have their prices assigned with the green universal scanner function. Once refilled and packed, you can then offer goods easily to the crew at any quantity.
Breaking the bank
None of the above quite satisfy your greed?; Want to take the station for everything it's got?; Inside the vault is a machine that allows you to siphon the cargo funds, allowing you to rob the station dry. Just don't expect security to stand by and let you take it. This is commonly considered to be a "major no-no" and will likely cause a biblical hammer of the entire cargo department going after you.