pallets are realativly easy to find. Our sears has three huge piles of pallets 'crate sides that they are throwing out!!! Check out tractor supply too. I've gotten in the habit of looking behind and besides stores for anything usable
I made mine out of leftovers from a new fence, plus wood from the old fence, and a heap of random wood next to my shed. Plus the old dog run we haven't used for years.