True, casting won't save you money, BUT it lets you shoot a ton more for the same amount of money, which is really what people mean as the cost per bang is dramatically reduced. I definitely don't have the discipline to shoot only cast only as much as I'd shoot bought bullets and thus reap any savings. What I do get is centre fire ammo that costs about as much as premium .22 LR.
Compared to buying even commercial cast, my pot, moulds and other gear was paid for in a single casting session. I don't spend less though, I just get a ton more shooting for the dollar. I could throw out my NOE moulds after every session and still be ahead compared to the cost of buying bullets.