The first order protocol, small and cheap
How to run your first order on a new vendor without much at stake.
The first order with any new vendor on Nexus Market should be structured to minimise what you lose if the vendor turns out to be worse than the page suggests.
Small quantity. Cheap product. Standard shipping (not expensive express). Standard escrow (not finalise early). Use the on-storefront message system with polite factual language. Encrypt any address you send to the vendor with their PGP key.
Wait for the order to arrive cleanly. Check it against the listing. If everything matches, that vendor gets a second order from you, larger this time. If anything is off, open a dispute early with clear evidence and move on.
The point of the first order is calibration, not commerce. You are buying information about the vendor, and the product is a happy side-effect. Buyers who skip the calibration step and place a large first order to a vendor they have not tried before are the buyers who write to the Bureau most often after something goes wrong.
Where first orders actually go wrong
Not in choosing a vendor. In the moment after: releasing escrow early because a seller asked politely, or continuing a conversation somewhere off the platform because it seemed faster. Both remove the protection while the order is still in flight, and both are requests that honest sellers sometimes make, which is exactly why declining them has to be a standing policy rather than a judgement about the person in front of you.