Plus Size Barbie
This has been my signature costume for years! Plus Size Barbie and Caveman Ken
Purchase a large wardrobe box (I found ours at U-Haul). Cut font off leave 2 feet on the bottom.
Purchase enough poster board of your color preference which will cover the entire box (generally about 10 per box).
From here comes the creativity. I used to spray paint the inside but my fiance (on the right) experimented with more poster board. He was a boy scout to his duct taping job made it all possible.