There seems to be multiple ways of looking at this. Either the lines are simple representations of numbers based on the records in points as graphics which would be good for one off maps, alternatively they are representations of value based on an attribute Value of a line. I would suggest creating a line Feature Class from all locations to all other locations, and then assign a separate unique ID for each line. Then you can create a join between your trade attribute Data and your linear feature data. The last stage is then to symbolise the lines based on the Quantities in your joined table. Then you can assign arrow size, directions and line information to each of the lines and customise.
Hope this helps, I am sure there are other ways as well,