Here's how to make your own....
You will need:
>4 x 4 x 4-inch plain white boxes (mug size...look for them near the gift bags at your local craft stores...aka Michael's, they come flat so you will have to assemble them)
>Bright yellow card stock, cut into 5 3/4-inch squares, you will need 5 squares per box, so plan accordingly
>White card stock, cut into question marks. You will need 5 question marks per box also...this is a little time consuming, but the end product is worth it! I used this to make a template...you will need to re-size your question mark to fit your boxes.
Assembly is simple, after your pieces are cut out, affix your question mark in the center of each yellow square. Then a yellow square to each side (except the bottom) of your assembled boxes. Carefully draw a black dot in each corner. And you're ready to go!
FYI....individually wrapped Rolo candies make great Mario Bros. "coins". We found lots of favor filler options here (and at a reasonable price :)