Although rules for conducting interstellar trading operations are conspicuously absent from the 2300AD Players and Directors Guides, the subject was addressed in a couple issues of Challenge magazine. I am aware of two articles that would be helpful to anyone running an independent trader campaign:
Trade in 2300, Author unknown, Challenge No. 29
Core Subsector, by Andy Slack, Challenge No. 75
Copyright laws prevent me from reproducing these articles here, but those not having access to the aforementioned back issues of Challenge are welcome to email me at freetrader2300@yahoo.com with questions.
Summary: This is the definitive article for conducting independent trading operations in 2300AD. Rules for determining world classification, buying and selling goods, expenditures and income, etc. are provided along with a trading adventure scenario.
Summary: This article takes the various worlds of the French, Chinese and American arms in 2300AD and rates them for Traveller: The New Era. This makes it possible to use the Traveller: TNE rules for running a trading campaign in 2300AD.