@Chemsick A living soil has three parts.
The base is your coco, or peat or whatever.
The aeration would be the lava rock, but like everyone else is saying, bulk perlite and vermiculite are cheap and effective.
Last is nutrition, and is really the only part that gets customized. Eggshells, Oystershell Flour, Gypsum, Basalt, Greensand, Bone Meal, Blood Meal, Guano, Manure, Kelp, Alfalfa, Crustacean Meal, compost, Vermicompost, Black leaf mold. The list is effectively endless. If you want one step and done, check out espoma hollytone. It’s mostly chickens and rock dusts.