That's why everyone should handload. When you do, the .45 ACP is price-competitive with the 9mm. A 230 grain bullet cast from wheel weights, loaded over 5.0 grains of Bullseye is pretty cheap.
Not really, it just relative. 9mm is still cheaper if you reload. I load both, and a lot more 9mm than 45acp these days.
Reality is, and it doesn't matter what the type of gun it is, 9mm is just easier to shoot well with (its just physics
), and not the pipsqueak that you often hear from those who insist 45acp is better. A good hit with either will give the same result, and a good miss with either will do the same. Whatever you shoot best with, in a realistic manner, just not target shooting, is the gun you want.
The only way to figure out what gun will work the best for you and why, is to give them all a good try, or as many as you possibly can, and decide that answer for yourself. Thats the only way I know anyway. I have, or have had, most of the different types of handguns, and shoot at least one of the basic types on a regular basis. A good example of any of them will work fine, if you are willing to put in the time and effort to learn the gun and shoot it.
SA, DA, DAO, striker, whatever, as long as you have a quality gun thats been vetted, the only weak point in the mix, is you.