Have you tried going to a Farming/Animal store?
Ask for greenhouse substrates... i also live remotely, but i've used FF so i know what it is. So while looking for an alternative, i found an european substrate that's very similar to the whole foxfarm mixture.
It worked like magic. And cost me about $30 for a whole 500L bag.
It's actually becoming standard practice to use coco + perlite + some extras in greenhouses all over the world.