Etsyer Wintercroft offers plans and instructions to make your own 3D polygon skull mask from cardboard.
The instructions and templates are designed to be easy to follow, so that the mask can be assembled by anyone, using local materials and removing the need for shipping. besides it's good fun turning a 2D material in to a 3D mask. The templates come plain white and you can decorate the finished mask however you like.
This mask is simple to make and the construction techniques are the same as my other masks. basically, if you can cut out shapes, match up numbers and tape edges together, you can build the mask. It is as simple as that. It takes approximately two to three hours to build from printing the templates to finishing the mask. The finished masks are pretty robust due the their polygon construction and will survive the wildest of parties.