I have to disagree with you on your comment about dogs and cats "systems not set up for people food." Dogs evolved in the wild, and they weren't eating the processed little biscuits that is dog kibble. Dog food is a very recent invention, and marketing has convinced people that this is the only appropriate way to feed your dog. I have two dogs and I can tell you that the one of the things that we never do is feed our dogs dog food. Granted, we do not feed our dogs what would typically be considered "table scraps" - fat from meat, leftovers off of our plates. Our dogs eat a diet that consists of raw meat, offal (things like organ meats - kidney and liver for example) and vegetables. Occasionally we throw in some grains like oatmeal - or stale bread. If I have a eggs that are past the expiration (shame on me!), I scramble them and feed them to the dogs.
How is this frugal, you ask? Well, I have two dogs and I spend between $350-400 per year to feed them. I buy meat from a meat distributor, and by choosing cuts that aren't popular with humans, but are still human grade, I keep the average price per pound to about 50 cents. Most, if not all, of the true "premium" brands of kibble are more expensive than this. Obviously, supermarket brand dog food IS cheaper, but you have to weigh the consequences of feeding your dog crap.
Vegetables come from my garden. It is often giant zucchini that got missed, and the itty bitty carrots and carrot tops that I have to pull in order to thin them out. Parsley is also cheap and plentiful.
Dogs fed quality food (whether raw or a PREMIUM dog food) are healthier, meaning less vet bills.
Other ways I save money on pet care:
1. Don't vaccinate every year. Many vet schools are coming out with vaccination protocols that recommend against vaccinating every year. Typically, the protocols suggest vaccinating every 3 years.
2. Don't let your animals roam. This can lead to fights and accidents with huge vet bills. I know a family who paid more in vet bills after their lab got hit by a car than it would have cost them to install a dog-proof fence.
3. Take other appropriate preventative measures, such as getting your dog on heartworm preventative. Preventing heartworm is a lot less expensive than treating it!
4. In terms of toys, I keep it simple. I have one dog that is ball obsessed. Inside, he has a giant tennis ball that I think cost me about $5 (I can't remember because I bought it 9 years ago). Outside, he has a "special" outside plastic football that cost $1 at Target (in the kids toy section, not the dog toys). I also buy sterile natural beef bones from a pet supply catalog. These last years at my house, and provide hours of chewing entertainment. I only throw them away when they get small enough to get caught in the mouth. If your dog likes stuffed toys, try stocking up at the thrift store. Pick ones that don't have pieces they can pull off and swallow.
5. Walk your dog. It is simple to do, free, and good exercise for both owner and canine.