You always free to advertise your in-game materials out-side the game.
Would be just the same as starting a selling thread on this forum.
Since we have no in-game auction yet it is also not possible to sell your materials with mark-up inside the game.
Still remember that we facing a wipe upon live release in 2014 so sharing your items seems to me personal a better option than selling them with mark-up.
You also conclude with saying there is not any sort of real cash involved.
Personally i really hope trades in the future could involve real life valuables, mainly thinking then about player vs player trades.
Well who knows what the future will brings...