So far I have my first exotic weapon, 'The last Word' which I just finished upgrading. I have 22 Strange coins. Xur is selling suros for 23 coins but he is also selling the voidfang chest armor for 13 coins. Also at the same time I recently got an exotic bounty for the super good advice machine gun and I'm at the part where it requires me to buy something from Xur for 1 coin. I am now unsure of which one to choose.