gunlistings.org - Free Local Used and New Gun Classifieds Ad Listings. Pistols, Rifles, Shotguns, Antique and Collectible Guns, and Gun Accessories. Los Angeles Co., California: Barter Online at - SwapGiant Anybody ever use these two FREE listing sites to list guns for sale/ammo/ supplies? Interesting sites. Some stuff WAY overpriced, but neat to look at. All are based on a single state search.