There was just a thread about someone only being able to find ammo at $130 for 50 rounds of ammo.
Good luck finding more ammo at $0.50 per round. Expect more to $1-2 per round if you do find it. Once you are out of ammo, will end up being $20-40 per clip to shoot it.
Save your brass and reload them, its honestly going to be worth it to start reloading if you don't already.
That being said, it is supposed to be a really awesome firearm. If ammo were available, and 1/4 of the cost I would consider owning one, but neither is the case.