Oh God....I did not know it would be so expensive to feed an adult!!

Any recommendations/links to start a Dubia colony and can you guys please tell me where you order your night crawlers/dubias/food? If they eat this much when fully grown its pointless to buy then by the dozen then at my local bait shop. I would need to order in bulk, who do you recommend for this? and how much would it cost per month to feed a full grown pyxie/ornate individually( an estimate)