We buried my brother in a homemade pine box. Not in LA County, and maybe that’s why it was easy and fine with the cemetery. My other brother made it.
It was good enough for all my people in the family cemetery right up to the Depression era, some were furniture grade wood but most were pine planks, built by family members, with a wake held in the parlor of the house.
But it’s illegal there now, a vault is required. I’d prefer the option of such a burial myself.