Hi,
Not to knock Reptayls' recipe or anything, just thought I'd share what we use to gutload our insects, as we feel that it is a great gutload and it is very cheap and easy to make.
Basically, we use a mixture of high-quality dog food, rabbit pellets, skim milk powder and dry baby cereal.
Rabbit pellets are really cheap and are very nutritious, but check the label and only get the good stuff (i.e. not Hartz or other such garbage). Stay away from labels that have corn as the first ingredient listed and stay away from too many ingredients that contain the word "meal" in it (as in corn meal, wheat meal, etc.).
As for the dog food, look for Wellness and Mother Hubbard; they are superior-quality foods that only use organic ingredients and low-temperature processing. Often times, you can get free samples from pet stores and/or feed stores. There are several flavors available so you can vary your mix; variety is key to healthy herps.
We use a coffee grinder to grind the dog food and rabbit pellets into a powder, then mix in the skim milk powder and baby cereal. The bugs love it.
Couple this with fresh veggies (dark leafy greens, carrots, etc. as suggested previously) and you're set.
Good luck!
Julie