.380 ACP is a specific type of ammunition made. 380 LCP is the name of a Pistol, made by Ruger which fires the .380 ACP round.
.380 ACP
There is no difference. ACP stands for Automatic Colt Pistol.
Nothing.
Nothing, two names for the same round.
The .45 ACP--which stands for AUTOMATIC COLT PISTOL is used in semiautomatic pistols. The .45 Colt is used in revolvers.
Nothing, two names for the same round.
The .45 GAP is a shorter cartridge than the .45 ACP. Developed for the Glock Automatic Pistol (that's the GAP) it does not interchange with the .45 Colt Automatic Pistol (ACP). Made for a smaller firearm, shorter action, etc.
ACP stands for Automatic Colt Pistol. They are the same.
I'm not aware of a .45 Magnum. There is a .44 Magnum. The 44 magnum is typically a revolver round, very high power. The 45 ACP is typically used in semi-automatic pistols. The 45 ACP is not as powerful compared to the 44 magnum (mostly due to the amount of propellant in the 44 magnum compared to the 45 acp).
There isn't a .40 ACP - the cartridge you're thinking is the .40 S&W. Basically, it's a larger cartridge than the 9mm, being essentially a shortened version of the 10mm auto cartridge.
25,000 to 28,000 pesos is a reasonable amount for a used ruger LCP