POSSIBLE SPOILER: A large pistol stash on top of a building in the Slums for those wanting guns early on(must have picked up or completed side quest with Dawud) : r/dyinglight
For beginners, go to this location for a gun, sorry for bad quality : r/ dyinglight
Dying Light: How to get Guns (FREE Pistol) - YouTube
Firearms | Dying Light Wiki | Fandom
Dying Light - Where to find 9mm Pistol (Gunslinger Side Quest)