everything thats been said thus far is spot on...
Heres my take;
I have not reloaded YET.. A few months ago i was at a local auction and let myself get caught up in the bidding and way over paid for a used MEC 650.. Probably about 110$ after buyers premium and tax.. After i got it home and looked it over, everything looks great EXCEPT the primer tray/tube thingie is missing. Still need to find that!
Fast forward to last months auction at the same place, and i picked up a bag of 600+ once fired AA hulls and a 500 count bag of unopened wads.. About 12$ out the door..
As has been said, theres no savings reloading 12ga. Factor your time, and your losing money or wasting your time in most peoples eyes.. BUT, for me, im looking at this like hunting deer or planting the back yard garden.. Hunting with licenses, permits, buck tags, guns, ammo etc is way more expensive than buying some common meats at the grocery store. Gardening, not cheap! and very time consuming! But we do it, its enjoyable and self reliance is rewarding.. So getting started in relaoding seems about the same ideals to me.. I want my teenage son to try a hand at it too. A fun learning experience..
And about that self reliance thing, being able to reload is huge.. I always say; i can hunt, fish, grow crops, i have guns, trucks, and can build anything. Me and my family will survive almost anything. Anarchy, blackouts, crumbled infastructure, colapsed economy, etc, etc.. Knowing i always have access to make ammo makes all that even easier..