9mm is the cheapest one (of course .22lr).
Of your choices my vote is for a 357Magnum revolver. When ammo was hard to find, I was able to find 38Spl in my area. And something of the size of a Ruger LCR 357 or Ruger SP101 works great as a woods/backpacking gun. For bears I carry a can of bear spray. Another choice for you would be one of the Ruger Convertible revolvers with the 357/38 cylinder and the 9mm cylinder.
With so many 9mm pocket guns are out there, I wouldn't buy a 380acp gun. The 9mm pocket guns are the same size and in many of them recoil is very pleasant.
My second choice would be .45acp.
Of your choices my vote is for a 357Magnum revolver. When ammo was hard to find, I was able to find 38Spl in my area. And something of the size of a Ruger LCR 357 or Ruger SP101 works great as a woods/backpacking gun. For bears I carry a can of bear spray. Another choice for you would be one of the Ruger Convertible revolvers with the 357/38 cylinder and the 9mm cylinder.
With so many 9mm pocket guns are out there, I wouldn't buy a 380acp gun. The 9mm pocket guns are the same size and in many of them recoil is very pleasant.
My second choice would be .45acp.