To make new cartridge cases from scratch takes about 25 steps with precision equipment. The old story: The first case costs $100,000; the next million cost two cents each.
For powder, a problem in today's world is a mix of federal regulations and company policies regarding shipping. Various fees for "special handling" and suchlike can run the cost up--unless you're buying in BIG quantities. IIRC, primers are regarded as equivalent to dynamite or some such dangerous material.
There are lots of places with pictures of cutaway views of bullets. They are precision-made, with varying wall thickness of the copper, and specific curves to the ogive at the front. Plus, such stuff as depth and diameter of the hollow point. "The first bullet costs $100,000..."
Steel cases can be reloaded, but they are far more likely to scratch both the resizing die and the chamber of a rifle. The military doesn't have to worry about such things.
Casting your own bullets is neither difficult nor expensive, particularly if you are good friends with somebody at a large tire store. Wheelweights work fine.
I've pulled bullets by holding the end with a pair of pliers and withdrawing the case with the loading tool ram. I then reloaded the bullets to see how much degradation in accuracy there would be. At 100 yards, very little. Good enough to hit a easily hit a coyote or deer.
It costs me about 28 cents per round to load for my '06. That's $5.60 a box for loads that will shoot inside an inch at 100 yards. I bought some el cheapo Winchester Silver Tips from WallyWorld for $8.00 plus tax, and got 3" to 4" groups. Duh? And I see very little premium ammo for much under $20 for 20 rounds. Premium ammo is almost as accurate as my handloads.
The "Big Deal" about handloading is that you not only have the versatility as to shape, style and weight of bullet, but you don't have to buy only "hot" loads. Your costs are less, of course, but there is the satisfaction and pride at doing well at something enjoyable.
And like I say, it keeps me out of the beer joints.
, Art