They have stated multiple times that they purposefully do not allow trading because they want players to earn the gear they acquire... and that characters should never receive items they cannot potentially use. so a Titan will never get a Warlock piece of armor. Personally I prefer it this way. Because I feel Auction houses ruin game economies. As for trading items between characters, you should be able to do that by putting it in the vault in the tower, then coming back and taking it with a different character. This game isn't about money, it's about gear - so currency has no relevance between players, which I feel is a good thing because, again, money always ruins online worlds in my opinion. Gold Farmers and such.