Card boxes are expensive. This does not make sense to me. It is a box, that you put cards in. That's it.
I had some leftover wrapping paper that I used to make the message board, so I decided to diy a card box. Quite simple really. All you need is a box, some wrapping paper, and some tape. The box I used is a 1/2 ream copy paper box. I picked it up at Staples for free. They will usually give you their leftover boxes if you ask. You could also use a shoe box, a wine box or a box that's used to send packages in the mail.
I wrapped the box in two parts-the lid is wrapped separately. This makes it easier to take the cards out, no need to unwrap the whole thing! I didn't bother to wrap the parts that you can't see. Leaving at bit of space where the body meets the lid is a good idea, it lets the lid slide on and off much easier, and prevents the paper from ripping. I did spray paint the box silver, since the paper is white I didn't want any text to show through. This probably isn't necessary for most papers. There is one seam, but if you turn it towards the wall no one will see it.
I cut a whole in the top with an xcato knife, and used some regular tape to adhere the cut edges of the paper on the inside of the slot, so it looks neater. You can see in this photo how I wrapped the edges of the paper and taped them on the underside. It looks similar on the bottom of the box.