Yeah, a sheet of upholstery foam, about 1/2 inch thickness, will cost you about £3.00, and then all you have to think about is glue. I'd recommend using a low heat hot glue gun, or if you fan find it, some craft stores stock a contact adhesive specifically for use with fabric thst costs about £6.00.
As for fur, when you have the head complete, cover it in cheap brown packing tape, mark where you want the parts of the. Fur to go, and theft direction you want theft pile to go with black marker, cit that out with a scalpel and useful the pieces as.a pattern.
Right, now that we're done with the technical bit, whqt species were you thinking of making? And what colours?