Amazon offers its Prime members the Wildkin Penguin Luggable Plush Backpack, model no. 90001, for $7.95 with free shipping. (Non-members can spend $35 to qualify for free shipping; otherwise, it adds $8.44.) That's the lowest total price we could find by $19. It measures 18" x 22" when open and converts to a comfy pillow.
Note: It may be available for guaranteed delivery by Christmas. (Availability depends on ZIP code.)