I recently picked up a Savage 99 in 308 Win. and made loads for it from GD IVI brass, GD M80 FMJ-BT 147 gr bullets, CCI 200 primers, and IMR 4064 powder.
Here's what it cost me per brand new round (all costs include 13% sales tax):
Case 0.27
Bullet 0.32
Primer 0.08
Powder 0.34
Total per round 1.01
Cost per 100 rounds: 101.35
Cheapest commercial ammo I can find (Federal American Eagle) is 1.35 per round (135.54 per 100) . The stuff I would normally buy (Winchester Super X) is 1.53 per round (152.49 per 100).
That IVI case is going to last a long time. I feel like I'll get at least 10 loads out of it, but let's say I only get 5 loads out of it. The cost per round for the next 4 reloads of the same cases would be:
Bullet 0.32
Primer 0.08
Powder 0.34
Total per round 0.74
Cost per 100 rounds: 74.07
So, assuming those cases last for 5 reloads, the cost for 500 rounds is:
First 100 rounds 101.35
Next 4 rounds 296.28
Total for 500 rounds 397.63
Compare with Federal American Eagle at 677.72 per 500, and Winchester Super X at 762.47 per 500.
I enjoy the reloading process and I love the look of the finished ammo, so the time involved is worth it to me.
I reload 223 Rem but I don't think the cost savings are significant there. I have a lot of 223 brass stashed away but I have to admit that lately I've just been grabbing commercial stuff from my stockpile when I head to the range.
For me the real benefit to reloading comes when you are dealing with uncommon or obsolete ammo. Having the tools and the knowledge lets me make ammo for things like 32 WSL and 7.5 Swiss 1882 Ordnance. Now I admit that those are not hard rounds to make. But I would never have gotten into the very cool firearms that shoot those rounds if I were not already reloading.