Usually in order to purchase wholesale from a vendor you have to have a 'for resale' tax certificate/tax id #, although I have heard of some allowing anyone who is purchasing in volume(say multiple whole bolts of fabric) to do so at the wholesale price.
I know about 20-25 years ago I purchased the fabric for square dance skirts for a whole club that wanted identical skirts direct from the manufacturer at a price lower than we could get it from the local retailer since it was several bolts of fabric. Whether that was true wholesale pricing or just a volume discount, it was a cheaper price.