cost of gun - already have the gun
ammo - what does one bullet cost or in your case 15 or more 
time - priceless
gas - didn't pass any today
So we have maybe a couple of bucks for the same thing that would cost you over 500 at the grocery store.
Sure change the reason you got the guns, to because we already have them? Nice one.
Or did you forget the question:
The question you have to ask yourself is what purpose will it be used for?
And if your purpose is hunting then that's why you bought the gun so factor that into the price.
cost of gun - A few grand
ammo - Depends whether you are wearing your glasses or not
time - I'm a goverment employee time isn't actually money
gas - At my age I don't notice what happens every minute
Sorry had to FTFY.
Although kudos for the Bucks joke.