I cannot take credit for the design of the card--I got the idea from Shelly Hickox (Stamptramp). She has done some amazing cards from a tutorial from Splitcoast Stampers. See it HERE
Shelly inspired my card with a card you can view HERE
Another card of Shelly's I used for inspiration is located HERE and it even has a little video showing how the card collapses to fold flat for mailing.
You can use the Splitcoast Stampers tutorial to make the box, or you can use the Eileen Hull Sizzix die to cut and score the box parts for you.