Just remember that you don't have to use gutload until the day before you feed the crickets to the chameleons. The whole point of gutloading is to ensure that whatever you feed them is still in the insect's gut (and not digested yet) when the chameleon eats the prey item.
So you can sustain your colony of crickets/roaches/worms on a less expensive diet (I use a mixture of baby cereal, powdered milk and grains, and then fresh fruits/veg for moisture), and then only switch over the ones you are going to feed to your cham the next day to the more expensive gutload the night before you feed them off. Your gutload should last quite long if you do it this way.
I also use the Adcham recipe that Kinyonga linked to - it's a great recipe, and it allows for some tweaking.