As long as you are not a felon and as long as you don't have any disqualifying misdemeanors, all you need is the following:
to purchase from a licensed dealer: a currently valid, government issued ID with you photo and address and the money to make the purchase. The dealer will process a background check while you are there.
from another individual: Just the money. No background check is required between two individuals. You should be careful who you buy guns from however because possession of a stolen gun is a problem if you get caught.
Only if you want to own one.
No
You have to be 18 to buy a long gun and 21 to buy a hand gun.
To purchase a gun, no. Anyone can purchase a gun as long as they meet the age requirement, aren't a felon, and don't have any disqualifying misdemeanors.
no
No
Two pieces of identification, money, be of legal age, and not prohibited from buying a firearm. Visit your local gun shop for more info.
Yes
18 for long gun, 21 for hand gun
yes
No
No