You will get a lot of opinions on this. There's basically 3 reasons to shoot a handgun, not counting hunting.
1: To plink and punch holes. Total purpose? To have fun.
2: To practice with the gun. To become proficient with it. So you become accustomed to how it feels when shooting different bullets. Total purpose? To be able to use it against and intruder or other form of self defense. When shooting a bad guy, you don't get to aim the gun like you did on the range. If you spend 5-10 seconds looking through the sites at the bad guy, you will die.
3: To shoot a bad guy. Basically you don't want to be here, but if you are, this is what #2 was for. Total Purpose? So you or your family doesn't die.
For #1, most people get the cheapest stuff they can find. Usually it's 158gr lead round nose. It could also be a lead semi-wadcutter or a full wadcutter. (Do a quick google on the wadcutters and it will describe it and pictures). Anyway, I go along with shooting the cheapest crap you can find for punching holes. However, I always recommend shooting at least 1 cylinder full at the very end, of whatever round you are going to shoot. I.e. If you are going to shoot 125-jhp 357 mag Golden Sabers (That's what I carry), then before you leave the range for the day, you should shoot 4 round. (The reason I say 4, is because it gives you the feel, then every 5th time you go to the range, it will be time to buy another box of the good stuff because 20 in a box will get you 5 times of practice with it. All other times, shoot the cheap stuff. That includes the cheapest 38 special you an find. Some people claim that you shouldn't use the cheap stuff. Personally, as long as you keep the gun clean and in good shape, you can shoot all the cheap crap you want.
Another suggestion I have. You have to realize that GOD FORBID, you ever have to really use this gun in self defense or in the home against an intruder, there is very little time for aiming. Plus, you pulse is going to be racing and you will barely even be able to breath. Throw all ego out the window, and realize that you are going to be scared SH*TLESS. That is a fact. I recommend that when you are about done for the day plinking, that for the last cylinder full of plinking ammo, you set up a fresh target. Get a red marker and make a circle about the size of a soccer ball or basket ball. Stand about 20-30 feet away from the target. Looking straight at the target and the gum in your hand at your side, bring the gun up as quickly as you "SAFELY" can, and without concentrating on "AIMING", point the gun at the red basketball circle and shoot. Put the gun back to your side. Take a deep breath and do it again. You don't have time to be looking down sites most of the time. If you know the bad guy is downstairs and you are waiting for him, that is different. But, that isn't normal. Anyway, Shoot that cylinder full and see if you hit the basketball. If you did, then you will probably hit the bad guy. If you didn't, or only a couple, then relax and try again next time.
That;s a main reason that ALL my self defense/home defense guns DON'T have adjustable sites on them. I'm not hunting with the pistol. Just like a computer; "POINT AND CLICK". DON'T THINK ABOUT AIMING. Know your target of course, but just "Point and Click". If you stop thinking about aiming, you will be quite surprised at how good you can shoot. Of course hunting and target matches is a different story.
So, cheapest bullet you can get Online, I can find 38 special in a case of 500 for between $70-$90. After shipping, it's still about $85-$100. That's $8.50-$10.00 a box including shipping. For home defense or self defense, I use 125g-JHP Golden Sabers or Hydrashocks. If the 357 mag is too much for you, you can get the same exact bullets and weight in 38 Special +P. Same everything except a little slower and a little less energy. Still very effective. For in home use, if you have apartments or duplexes, the 38 special +P is definitely better than the 357 mag. Later... Mike....