My wife and I are actually looking into getting a dragon. A herping buddy in town breeds dragons and he will be the source when we get one. My wife and I both had iguanas when we were growing up. I also already have caging, lights, etc. Just doing the rest of the research before taking the plunge.
Anyway, what I was going to suggest is to grow a garden. Which I'm sure would be alot different in northern states, etc. In Louisiana we have a garden growing year round. The greens, mustard, collards, etc. are grown in the cooler/cold months, but there is plenty to grow in the summer. My iguana loved cut okra, squash flowers, squash, young chopped green beans, corn cut off the cob, etc. I've read that dragons will eat hibiscus leaves and flowers. Also dandelion flowers.
If it's picked right off the plant it's fresh.