I started reloading decades ago, after I bought a 45 caliber Ruger Blackhawk (without first checking to see what it would cost to feed it ;^). That was before cowboy action shooting got popular, so there wasn't much demand for .45 Colt ammo, meaning not much factory ammo out there, and the cost of my first box about gave me a heart attack. So I bought a Lee hand press, a set of dies, and a set of Lee powder dippers. Didn't have a whole lot invested, and it turned out my .45 reloads shot fine, and were cheaper than factory ammo even if I bought new brass & only used it ONCE (of course, I reused the brass which saved me even more money).
How much you save depends on what you buy for equipment & what you pay for components, versus just buying factory ammo, so it varies depending on the calibers you shoot, and what you want out of your reloads. I've had good luck buying used equipment, items that are on sale, and stuff from the "Closeouts" section at the Lee Precision web site. I also shoot a lot of cast handgun bullets (which I usually pay 2-5 cents each for), and I watch for deals on jacketed bullets (try to keep those around 10 cents or less). Plus, I've had good luck buying propellant at gun shows (got a new/unopened 1 pound jug of Varget for $20 a while back ;^). So, I've been chugging out 9mm reloads for about $6 a box, and .30-06 for maybe $8 a box.
That approach works for me, but obviously YMMV. I suspect that folks who buy top-shelf equipment and components have to produce high volumes to cover their costs, or else they do it just because they love reloading.
As always IMHO, FWIW, YMMV, etc., etc...
