Not to weigh into this too late, but it seems that people are looking at trading as if it is a quick easy way to make credits to buy whatever prize ship you want.
That isn't the point of trading. It is supposed to be as viable a game play choice, both in regards to enjoyment and money gain, as any of the other primary game play options (pirating, bounty hunting, exploration).
If they added a galactic ebay where you could just scroll down and find the best deal, then you completely remove the game play aspect of trading, and it becomes nothing more than a mundane milk run to farm credits.
There has to be an element of risk, and an even bigger element of unknown. Without that, the risk vs reward will never match up to the other game play choices.
If you want to make money trading, then you have to learn the game just as you would if you intended on becoming a bounty hunter, or a pirate, or anything else.
The galactic map gives you hints to look for, such as if the system is industrial, miners, agricultural, etc etc. That's all you need to go on.
In regards to recording what you've purchased/spent, that sounds like another thing I might have to add to my elite cockpit build - a cargo data logger!
