38 minutes ago, meilodasreh said:Stuff will start to show up in the trader's inventory when you reach a certain gamestage.
Actually, it is not Gamestage but depends on the Traderstage. This is a separate value that is based on your level, the quest level at this trader and the Daring Adventurer level.
WaywardEko made a video that explains it more in detail: https://www.youtube.com/watch?v=xLvOtD7Uv14
There is a pinned comment below the video that corrected for an error in the calculations.