For slugs and large buckshot, casting and reloading trumps any sale, anywhere, ever. If you shoot alot, you'd have to start printing counterfeit $20's to save the equivalent amount.
I've never bought a slug from the store, the price is just ridiculous, I couldn't beleive it.
I was already loading for my shotgun with my 45 dollar MEC reloading press, and casting bullets for my blackpowder rifle with a cheesy 15 dollar hotplate, old steel pot, and small bent ladle.
I know that sounds like a joke casting setup, and but I had been given a free Lee mould for my muzzleloader, and I really just wanted to try making a half dozen bullets for the next weekend before I invested in a "real" casting setup. Then I once I got the hang of it, was suprised how fast I could churn them out, and asking on castboolits casting forum revealed alot of people did that for years before tool lust got the better of them.
Last time I bought lead from the scrapyard it was a buck a pound, summer before last. I should call and find out how much it is now. Alot of guys scrounge free lead, but I don't own a machinegun.
It was easy to learn, as easy, or easier than learning to strip and clean a gun.