Trading: yes, but with TAX penalties on GIFTS
In-game items trading with others could be fun, but could be abused on many aspects.
There are in-game market places and stock exchanges in many mmorpg-s,
I traded for some time in RuneScape.
I do not like outside of the game trading of ingame items for real money,
like "Virtual goods auctions on EBay", because the game would be "cash for win"
type, like EVE, and this is major reason I do not appreciate that type of games.
Because E.D. is "TRADING game" i suppose developers already had conception of what kind of PvP trading interactions would be available, and how to avoid possible manipulations, similar to this one:
http://en.wikipedia.org/wiki/Gold_farming
My reasoning is this:
1. In real life: friends and family would help each other by lending or giving away relatively small sums, needed to survive. When large sums are in question, like for buying a house or giving a car for a present, authority want to know about it and there is obligation to report and being TAX-ed.
2. In real life: trading items or services without TAX included is called black economy.
My proposal would be:
1. Trading between to players should be by the price list of "current location", transaction is TAX-ed on seller by some percentage (imposed by governing faction of current location)
2. Gifting (Items/money for nothing in exchange) should be taxed progressively,
for example:
Value Gifted / TAX %
----------------------------------------------
1 - 100 CR (filled fuel tank value) Normal "Added Value Tax for seller"
100 - 1000 CR (basic weapon value) 2 * Normal ...
1000 - 10000 (basic ship value) 5 * Normal ...
10.000 - 100.0000 ( real estate value ) 10 * Normal ...
100.000 - (...) 20 * ....
This is my suggestion.