What's the price difference between Hornady ammo loaded with a premium lead bullet, vs the same thing with a Barnes? Next to nothing I'd bet.
Lead free ammo is more expensive for two reasons. The biggest reason is they don't make bargain brand ammo, it's all match grade/premium ammo, or defensive ammo in the case of handguns. In these cases, they're comparably priced to an equal lead product. The second is simply economy of scale. There isn't enough demand for it. If they outlawed lead ammo in usa/canada, they would be forced to produce more and cheaper lead free ammo. Copper is more expensive than lead, for sure (3x the cost basically i think?) but the rest of it, the brass case, powder and primer are no different.
Therefore, prices wouldn't go up nearly as much as most around here seem to think it would. Economies of scale and bigger consumer demand would keep prices quite close.
Of course, it would eliminate cheap surplus ammo because there is no way the military would swap, and the economy of scale would only work if the USA banned it, so I'm not down with any Canada only bans, that would really suck.
As for lead coming from the earth, that's a really weak argument. Uranium comes from the earth, and is even denser than lead. Should we switch to that?