It all depends on what you pay for your components...
Buy in bulk from a wholesaler and you'll load for far less than the poor guy who has to buy his boolits and primers 100 at a time and his powder 1 pound at a time.
So true.
The true cost savings per round are found in the larger calibres.
Go buy 300 Win Mag.
20 rounds for $40 or $2 apiece.
Now go do the reloading route. I'll use $40 as a simple basis and all purchased components (Non Bulk.)
Primer $0.04 per round ($40 per K)
Powder $0.42 per round (say 75gr and $40/lb)
Bullets $0.40 per round ($40 per 100 Interbonds or whatnot)
Cases $0.40 per round (Assume 5 reloads per case and you bought a box of factory ammo to get the cases $40 per 20, reloaded 5 times)
So suddenly reloading costs are $1.26 a round and you save nearly $0.75 per round. That includes buying Factory ammo first just to get brass.
So for every 120 rounds you spend $40 for the initial factory ammo and $126 for the reloading life of the cases.
Versus 120 rounds of factory @$40 = $240
This is also where volume comes into play. You save more per round with larger calibres, but if you shoot lots, then it also makes a good reason.
Save $0.75 per 300 win mag round, tailored to your firearm for accuracy.
Shoot 50 times a year, you save $38 over factory.
Save $0.20 per 9mm/.40/.45/etc... also tailored to your firearm. Shoot 1000 times a year, you save $200 over factory costs.
As was mentioned. Cast bullets = Cheaper. If you cast your own, you can minimize the costs in that area. Buying 8lb's of powder = price reductions.
Primers, not so much. Cases? You can have cases last 1-2 reloads or dozens, depending on your load hotness, case design and sizing methods (Plus annealing).
The biggest requirement for reloading is time and usage. Time you are willing to spend for your needs.
I know a few hunters, who use a box of ammuntion every two years. Would I recommend reloading to them? Hell no. I do ask them for their brass however.
Some IPSC guys? 100K a year in a single calibre. Reload time = less range time. So they spend $4000 on a high end fully decked out reloading press. Time for reloading? 8 days for the whole year, and total savings of $0.20*100k=$20000 over factory. Press setup pays for itself in two days of effort.