It seems interesting in some way.
(a) why gold for ammo and not dollars? It's not a key part of the experience, so why is price so high?
(b) it implies you only get ONE round for 150 gold bars. Clearly, that's not workable. So maybe it's more. Do you get a supply for all your weapons for one 'fight', one 24-hour day, or for all time?
(c) does it have a material effect on shooting? Or just for fun? Do 'sniped' enemies do a dance of death when hit by one? Or does it have no effect at all?
We need to know stuff like this to make economic and sporting decisions....