Have everything given a numerical value that needs to be equaled for the trade to be successful. For example my friend has 3 Gally's I need it he needs my Fatebringer. So Gally is worth 50 points my Fatebringer is only worth 15. Maybe every 500 glimmer is worth 1 point. Let's say No Land Beyond is worth like five. So by the end of the trade I would have to give up Fatebringer, a substantial amount of glimmer and probably some other exotics or legendaries I would probably rather hold on to (I like to collect.)