Container-growing mangoes/avocadoes, any tips on bulk soil mixing to save $$$?

[JakeFruit]

Soooo, I'm happy with the soil mix I've come up with, but now I'm sweating how much it costs. Coco coir, pool filter sand, perlite, earthworm castings.....it's pricy stuff by the bag when you have a full-blown grafting addiction. I have all these grafted seedlings in tree pots, I'm doing the math and realizing I'm going to need something north of 50 gallons of mix when I upsize their pots in a few months. I'm going to keep using my soil mix for favorites, but I want to also give trees to my family, friends & neighbors when they are about 3 gallon pot-sized big (I'm giving them free trees, but not my pricey mix). There's a Big Earth near me that sells bulk soils https://bigearthsupply.com/product-category/soil/bulk-soils/. Do I just buy a yard of compost soil, yard of sand, and a yard of top soil to mix together? How do the nurseries do it and keep costs at a minimum?

[spaugh]

Compost and sand and perlite would work. 

Some of the nurseries here just use the native decomsed granite soil by itself. 

[Bush2Beach]

You can buy a 6 cu ft bag of perlite.
1/2 yard of sand and 1/2 yard of compost .
A 3.5 cu ft bag of sphagnum peat is good for some mixes, probably unnecessary for Mango’s.
Buying bulk and making your own soil mix is always a winner.

[JakeFruit]

Thanks to both suggestions. Guess I need to find a spot in my yard for a few big piles of mix ingredients. That should make my wife happy 

[slopat]

Sorry to interject, but whats the advantages of having pumice in the mix that some recipes also have?. I like the ingredients listed here because they seem to be readily available by the yard.

[spaugh]

Pumice is a better material compared to perlite.  It weighs more and doesnt float and also has a better structure for holding water and at the same time being breathable as it dries out.  It also costs more than perlite.  Im a big fan of pumice in soil and prefer it over perlite.

The cactus mix I use for my plants has pimice, sand, and compost in it.  Thats what I use for my mango and avocado seedlings.