To answer that is impossible. Some calibers have brass that is $3-5/ just for brass, so how many firings do you get per brass, impossible to know. Large caliber premium bullets are the most expensive component.
Several years ago, a box of 20 factory 375 Rum was $109/box. My cost to reload the same was about $30 for powder, primer, and projectile. Like i said it is hard to say or know how many firings per brass, the other thing impossible to know is availability of components. However, if components are hard to find, then so will factory ammo.
A low volume shooter, that sticks to non magnum ammo in calibers found in the Walmart ammo lockup, saves very little. It is when you go into non cookie cutter calibers or precision that the savings are found. Same goes for shotgun. One does not save building low power trap loads. The saving is in high power hunting ammo or the sub gauges.