Affordable dog beds are difficult to find, plus they don’t often provide much support for arthritic, geriatric dogs. My Labrador Retriever sleeps on a standard crib mattress and he loves it. Old crib mattresses are readily available at garage sales and thrift stores.
I paid $10 for the mattress and 50 cents for the crib sheets. The mattress also has a plastic cover that’s easy to wipe clean, and stripping and washing the sheets takes hardly any time.