Before leaving town, I decided to snag one of the new Sig Sauer P238 .380 Nitrons. I consider this pistol a very expensive backup. My concealed carry weapon of choice is a Sig P239 SAS 40 caliber. I sometimes carry a Glock 26 9mm.
"Mouse guns" aka "pocket pistols" are very popular now. In fact, they are so popular that .380 ACP ammo is extremely difficult to find. If you are interested in this topic, google sig p239 and search it on youtube.
I paid more than I should have for a "backup" pistol but I did get the best price available using the Sig Individual Officer Program.
I own a S&W .38 revolver, S&W 357 revolver, Glock 9mm pistol, Sig 40 cal pistol, and now a Sig .380 pistol. I am done buying handguns in this lifetime!
BTW: The largest AND the most effective weapon (and the least expensive) I own is a Remington 870 pump action 12 gauge shotgun. The smallest and least effective fire power comes from this pistol, which is the most expensive gun that I have ever purchased! Go figure?