We did this as well when I was little, but with rats and mice. The pet shop would buy all our extras for store credit for other animal food we needed. I can't believe how expensive rats are now! It costs almost $7 for a frozen one at the pet store now. Unfortunately, now the only pet store in town is a chain store so I doubt they would buy any from me.

** as of now I'm raising crickets and mealworms for my animals, and I'm pondering the idea of selling as bait.