Same as it is today.
18 or 21 depending on if you are buying long gun or hand gun ammunition
So long as you may legally possess a firearm, no.
Depends on which gun you are buying, but in general, yes, it is. Contact the New Jersey State Police for additional information. This is a fairly complex process and takes several months to complete.
As long as you go through a trusted website, buying anything online is safe, so make sure there are good reviews before jumping the gun and buying it.
Find a gun you like, have money to buy, be 18 for a long gun, be 21 for handgun, passs background check, depending on the state, take gun home or wait 3-7 days to take gun home
no
Quality
Yes. If you lie on the 4473 and get caught.
The process for buying a home in Spain is much like the process for buying a home in America. The major differences being the fact that you would be buying a home in a different country.
The exact same laws in effect when buying firearms from a store, shop, or private citizen apply at a gun show. The process of buying a firearm at a gun show is no different than it is to buy a firearm elsewhere.
Explain how the buying process for a product like soap would be different from the buying process for a luxury or durable item such as a car.