4 rockets to destroy a Stone Wall. That's 5,600 sulfur in raw materials.
2 C4 charges to break a Stone Wall — roughly 4,400 sulfur plus metal fragments and tech trash.
10 satchels to destroy a Stone Wall in Rust. Satchels have the best damage-per-sulfur ratio on soft sides.
The cheapest explosive option for a Stone Wall is 46× Beancan Grenade at roughly 2,760 sulfur.