From page 93 of World's Greatest Toys, which addresses both previous posts:
"Mego developed the “Super-Hero Carry Case” designed to hold four figures. The vinyl case has a cardboard insert folded to create four compartments. The plastic handled Carry Case allowed kids to transport their favorite Heroes to countless recesses. Available for several years, the exterior can be black, brown or blue vinyl. The interior is either white or red. The graphic on the front remained unchanged throughout production; attached with double-sided tape, the adhesive rots, leaving a brown stain. These cases are not scarce today, and command very little on the open market."
Hope this helps.