Got a Big Dog?  Need a Big Bed? Crib Mattresses are perfect!  They are less expensive than fancy orthopedic dog beds and offer good support and cushioning.  They are easy to wipe clean and don’t absorb body fluids that are sometimes part of life with elderly or ill dogs.   Add your own mattress pad (which can absorb a LOT of liquid) and fitted sheet which are easy to change and wash.  You can get a mattress anyplace that sells baby items or I often find them at garage sales for $5-10.