1 rockets to destroy a Wooden Door. That's 1,400 sulfur in raw materials.
1 C4 charges to break a Wooden Door — roughly 2,200 sulfur plus metal fragments and tech trash.
2 satchels to destroy a Wooden Door in Rust. Satchels have the best damage-per-sulfur ratio on soft sides.
The cheapest explosive option for a Wooden Door is 6× Beancan Grenade at roughly 360 sulfur.