I make loads of beds for our Fur-Babies, as does our group, when we run out of own Fur-Babies to give them to we give them to Charity Shops and Animal Shelters and they cost next to nothing to make!
Take a pillow case and stuff them with all and I do mean ALL your quilting off-cuts, threads, fabrics and batting, stitch across the pillow case occasionally so it makes pockets, that way all the stuffing won't go into a ball when washed, (they do wash superbly). For smaller size ones for kittens, cats and puppies you can two out of one pillowcase!
Here is a pic of Muffin's favourite one, at present
It looks dirty but that is because she always takes her bones and chews onto it and she hates me washing the delicious smells away!