When I take a break from welding I rummage in the trash cans to see what other people throw away. That's how I found a piece of metal that said, "I could be a dog head." Railroad spikes are always available near train tracks and make great legs. Try your local motorcycle repair shop for discarded springs.
Be sure to listen to Prairie Home Companion on NPR. If you're lucky they'll have a skit about Crispy The Rescue Dog. Arf Arf.