Long story short it's a screwed system. Spend hours on end grinding for enough coins to buy primary legacy engrams in hope to get bad juju or mida multi tool but instead the game gives you the year ones and the crappy hand cannons. Then you get an exotic drop that rewards the same guns you just bought. Spend a few more hours, more like a whole day, and then Xur is gone by the time you get enough coins to buy another. #stupid #fubar