My suggestion here is to have some skins/effects purchasable instead of one time buy. I think the should be character only, not account purchasable. I like to change the look of my character often and find the optimal look. Hard to do with the current system as you can't go back to ones you bought for free. I do see how this could be abused with /trade, so I think there should be a separate NPC for skins you have purchased before, that when you trade the items reverts back to their original form.