depends what kind of Nerf gun. but your best bet is eBay.
it could be around 5 or more
You have to be 18 to buy a long gun and 21 to buy a hand gun.
Nerf toys of if you dare... a paintball gun.
You most likely have some sort of problem with the new one. If it is the Longstrike, Recon, or Longshot, try removing the barrel. If it is anything else, than your old Nerf gun is really well-made and you should give kudos to whoever got it for you or whatever store you bought it from.
You could find comprehensive information about the Nerf Rebelle Heartbreaker from their website, hasbro.com. There is usually no danger involved with the nerf gun provided the children playing with it are at least 7 years old.
At a garage sale, eBay, or your local Wal-Mart.
In the US, 21 years old.
18
Yes
18.
11 to play at fields, 18 to buy a paintball gun.
18 for a long gun, 21 for a handgun.