Look at for sellers of reptile food for insects. Mealworms are super easy to breed. Pet stores will also carry crickets and mealworms but you pay more for them. I use to order crickets and mealworms for my lizards from LLLreptile.com. You can also easily breed a few different species of roaches, they are nothing like the german roaches that infest peoples homes. I use to raise dubia roaches, they are tropical spieces that need heat to survive and reproduce. They don't climb smooth surfaces or fly, though the males do have wings and can glide a little. Crickets are a bit more involved to breed but can be done. There are a few other species of bugs but they are either harder to breed or more expensive to buy like silkworms, hornworms(never feed wild hornworms, they are toxic), superworms, butterworms and black soldier fly larvae. There are many companies you can buy from so look around.