Lol. Most of my critters pay for themselves, that's how I justify it. Although hubby isn't always happy about them, when it comes down to it, we've been broke a few times and the critters have brought money back to us when we needed it.
The worms/beetles are sacred here, lol. They're used to feed our own critters (fish mainly) and cut out most of the feed bill, plus I sell extras as starter cultures for other people to breed their own live foods. Whatever processed foods that I have to purchase for the fish here are bought in bulk and then the extras are sold off. That way I only have to pay bulk pricing, but without worrying about not being able to use it up in time.
The rats, they're pets, but I also breed them to feed the snakes. They're fed on poultry food and table scraps, because of the similar nutritional requirements between rodents and poultry. This cuts feeding cost on them ($.33/lb for poultry feed beats $1.06/lb for rat feed). Then, the babies that are fed to the snakes save me $26 per week (crazy what the petstores charge for feeders!). The snakes are being kept as pets, but once they're old enough, I hope to breed them and sell offspring to cover the cost of keeping them. Excess rodents (like I said, occasionally I'll buy a pregnant mouse at the petstore) are sold to the petstore or to locals.
The fish are bred and sold as well, and plants that are in their tanks are grown out and sold.
The dogs and cat, well, they're free-loaders here, lmao.
But, all in all, my hobbies pretty much pull their own weight.