I only received the game yesterday and have only put in about 6 hours, so the following problem could well be caused by not having reached very far into the game, but I downloaded Darren Malphurs excellent Cargo software (you input your starting point / destination and it computes the best trade) and it told me the best trade in the New York System was to buy Light Arms at Detroit Munitions for 140 and to sell them at Baltimore Shipyard 280.
However, on arriving at this destination the selling price was 140. The highest price I've encotered so far is the Battleship Missouri @ 180. This post is no way intended to diss the hard work of Darren, I admire anyway who is prepared to put such a lot effort into a project that helps many people for no reward, but I wondered if any other gamers had experienced similair problems. Is the program accurate or am I doing something stupid? Could any one suggest some good trade routues within the Liberty system?

All I have in this world are my word and my balls; and I don't break them for nobody