If you truly want a box a good department store that sells winter coats or furs may have one large enough. If not, you could purchase a plain box at the post office or thru a moving company to wrap it in. If the box has writing on it, you can check to see if it is a box made with the 1" overlap on the inside side. IF it is, it's pretty easy to un assemble it and turn the box inside out putting the plain side on the outside and the writing on the inside. I've done that trick many times.