We found it cheaper to buy laminate flooring that comes in boards; so we put some insulation under that (it came on a roll that we cut to size) then we laid the flooring on top and put beading around the edges, fixed with nails.
To insulate the walls, we cut polystyrene boards to fit the panels of the shed, then used plywood sheets to seal it all in. It took FOREVER but it was very worth it, the shed is always warmer than outside and not drafty. We also painted everything but the floor in Cuprinol cottage cream, so it's nice and light and wee-proof :lol:
Not got any pictures to hand, but hope that helps a bit!