I hear ya, I only buy the exotics off xur if I think I will use them. If not I just save for the next week. Never buy more than one. If I really like the weapon then I will just swap it back and forth between characters. My luck I would buy 2 and then get one from somewhere else. With the bounties though, I will do them and keep the original then the 2nd time around scrap them if I need the energy for another weapon.