In MOST of the US, you may sell an ordinary rifle, shotgun, or handgun directly to another resident of your home state, so long as you do not have reason to believe he is not allowed to own a gun. But some states have restrictions, and you did not tell us what state. So we really can't give you a good answer.
It all depends on the country and location where you live
Assuming this is a firearm you own, you can sell it to a gun shop, give it to a friend in your state that is an adult and able to own firearms or contact your local law enforcement officials and surrender the gun to them.
depends on where you are, but you can always take it to a gun dealer and have them sell it for you. Procedure varies from state to state.
Sites such as Craigslist, eBay, or local classified is the best place to sell your gun for a low price.
Yes they do sell gun safes along with many other things at Cabala's. There is also a gun library at Cabala's.
You can sell it at a gun show, you can sell it through classified ads (if your state permits it), you can sell it on consignment at a gun shop or sell it to the gun shop, you can sell it online at websites such as Gun Broker/Auction Arms/Guns America/Cheaper Than Dirt Classified ads, or you can post "WTS (Want to Sell)" ads on forums, or you could even sell it at a garage sale if you so wished.
No.
gun shop, ebay, gunpartscorp
Gun store.
eBay is the best way to sell
Yes
Find a better friend.