Making money, or credits, in Starfield can take a lot of time if you don't take advantage of some of Starfield's more disreputable activities. The easiest of these is finding and selling contraband. As far as we've seen possession of these yellow-marked items has no impact on companion relationships, and unless it's a UC or Freestar Collective scanner, no one really cares if you have it.
Contraband are illicit items like harvested organs found in enemy buildings and ships and locked up in security stations. Upon entering the space around major settled systems locations the local security will scan your ship upon entry in search of contraband. The only way to hide it is by having shielded cargo or by fast-traveling out of the area in the few seconds it takes them to scan your ship. You can learn how to get shielded cargo here if you insist on bringing your contraband to New Atlantis or another major settlement, but instead, we recommend you save yourself the credits and sell your contraband when you get it.
The easiest and arguably the best place to sell contraband is The Den, a space station in The Wolf system that's just east of Sol and northeast of Alpha Centauri. You won't be scanned upon arrival even though The Den is a UC military structure. To dock your ship at The Den you'll need to get within 500m to see the button prompt show up. After entering the station you'll find Trade Authority past the entryway and to the left.
This Trade Authority vendor has 11,000 credits, making it easier to sell more in less time. You can reset the vendor's credits by waiting for a total of 48 hours. Sit or sleep for 24 hours then do it once more. Return to the vendor and their credits will be rest to 11,000. There are a few chairs
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