Since my "collection" consists mostly of a few pets and not too many snakes I buy mine from the local PJ Pets.
But, my local store employs a herpetologist so he made sure they get decent feeders at a good price.
My price on individual purchase meets or exceeds the price you quote for your bulk orders. Of course they buy in very large quantities and can re-sell at lower than shipping just a few packs to an individual person each time.