This is a question that my gang has dealt with every few years for50years. Let me take a stab at how myself and 4-5 buddies have approached it over 5 decades. First, if you have kids and wives and 2 jobs, ignore the following.
If you shoot a lot of rifle rounds it probably matters. If you are retired and can arrange your day, or can sit on the porch and size 500 357s cases then a day or two later handload the primers you have lost very little time for "productive" things. My buddy became a surgeon. Once he called and asked what I was doing. Changing the oil in my diesel truck. Why do you do that he asked, me--saves money and not a big deal. He replied, I have no idea where the oil filter is on my SUV. Later we would joke that he was highly educated and had forgotten how to even change his oil--he was raised poor. But as AK Hunter says, why save $10 when he would make $300 an hour when working. And, he was a surgeon, breaking a finger would lose big money. All depends on your choice, everybody has 24 hours each day, just depends on how you choose to spend them.
I have lots of gun, 2 Weatherby calibers, I like to shoot the 257 as I said before, my gun shoots under 1/2 inch basically everything. Factory ammo is $50-$80 a box, $2.50 up. I shoot that gun more than most folks because I like to shoot things with an actual deer gun a long way off. I loaded and shot 200-300 rounds last year. I make my own brass out of 7mm Mag and use mostly Sierra Game King, about 30 cents, 35 cents powder and 10 cents primer. Even with new 7mm brass, that is about $1.10 or $22 a box the first time and 85 cents or $11.60 per box. That is ammo that will shoot 1/2 inch groups. 100 grain bullets at about 3,350 -3,400 fps. I load 75 grain Varmint bullets, 75 grain HP and 87 grain spire point up to 3,700 fps. These are not cheap bullets and if you could find them, they would be $60-$80 per box. I shoot 200 or more per year, that is $600 or more savings, most people do not do that.
I shoot rifles in 45-70. Any factory ammo is over $40 or $2 each. I can cast a 340 grain bullet, and powder coat if I want it hot, or load down. I can load a Buffalo killing bullet, for........
Bullet---$5 cents, primer 10 cents, powder-17 grains Unique 12 cents. That is 32 cents or $6.40 per box plus the pro-rated cost of the brass. They never wear out at those levels but if you apply 5 cents, then a 37 cent load, big deal. If I load JSP bullets the cost is about 38 cents powder, 50 cents bullet and 10 cents primer or 98 cents per, about half the price of factory. I cannot shoot many of them, they beat me up.
I do find by buying powder coated cast bullets I can save a lot on the common pistol bullets I load. Two days ago I bought 500 bullets, 40 cal for 10 cents each. I load them in 40 SW, 400 Corbon and 10mm. All factory 400 Corbon is $2 or so a round, 40 SW is cheap and 10mm about $25 abox or 50 cents each. I can load them for 10 cents primer, 7 cents powder, and 10 cents bullet. That is 27 cents or $13.50 a box, and I load them full power.
You asked about 9mm, 45 and 357. I have rarely loaded 9mm, when they are under $15 a box or 30 cents each, your diminishing returns sets in pretty quickly. Your 380 is one you need to stock pile, they disappear and get costly. They are a pain to reload. I have about 1,000 cases ready, I hate to load them but I load for 3 family members.. 45 acp is one that I load also, I shoot it in the 1911 and three wheel guns. I even load them with round balls, my cost on those is 10 cent primer, 4 cents powder and maybe 2 cents lead cost, for my 154 grain cast round ball. That is 16 cents each. I even load some of those in pickup steel cases. They are a hoot, and 16 cents a pop, quite fun.
Last is your 357. I have both Rossi and Marlin 357 levers. I have loaded for one since 1981 the first year they were made. Levers are not known to be accurate. My 357 Marlin with 125 grain Remington bullets will shoot 1.25 inch groups at 100 yards. Factory loads are huge, like 3 inches or more. You can buy 357 ammo now for about $30 a box down from $35-$40. Unless you scope your Rossi it probably does not matter to reload for accuracy. My Rossis are not that accurate. That said, you can buy powder coated cast bullets for about 15 cents, 10 cents primer and about 10 cents powder or 35 cents or $17.50 per box. Not for hunting anything like deer but for fun, turkeys, coyotes or anything else they are great.
You are loading the 357 for both rifle and pistol. My experience is that if I develop a load for the rifle, then that load is great for the pistol as well. If I try to get something faster burning for the handguns, then they may lose velocity in the longer barrel. That said, load them all with 296 or 110 and forget about it.
So, not to be boring but I do not need the savings by reloading, I enjoy reloading and I enjoy doing it cheap. Thumbing my nose at the many scalpers that take advantage of us poor hunters and shooting guys. Just my opinion, but go walk around a gun show and check prices and you will see why Isay that.
And last, there is value in creating something. I once cast a 365 grain bullet and killed my first black powder deer at about 80 yards. The deer was trotting in pouring rain and I made a lucky shot. The fact that I poured that lead is something that I tell every none when they see that deer on the wall. I probably shoot 80% reloads these days.
Anyway, just some thoughts. Either way, as AK Hunter says, stack em deep, either loaded or components.