I currently have a pair of Hercules Beetles. Right now their substrate is eco earth and spaghnum moss. I would prefer to buy a good breeding substrate rather than make it. Thanks!
What your asking for is hard to find it, it would just be easier to make it, you would be saving money and basically getting it for free. If you actually want to get really good Hercules substrate, they are out of the county and you need permits to import soil. Here is somewhere you can buy good substrate from http://rhinobeetle.co.uk/index.php/shop/all-products?virtuemart_currency_id=52&keyword=
There is a new online beetle store (based in the US) selling a premium quality of beetle substrate. They are actual company (business) now, and handling quite a different beetle species as well as rearing supplies like substrate, beetle jellies, etc. Here is a link to it: