I will walk you through how to make a mask but you can choose what it will be. There are many sites online that provide free printouts. You can modify the design how you wish.
I also made a robot mask for my toddler, so the options are endless. For my toddlers mask I used a 2 liter bottle to form it for the forehead and then for the nose area I just taped a piece of cardboard to the bottle. Just something small enough to create a curve for the bridge of the nose. I followed all of the steps below (excluding step 2) and then glued aluminum foil to the outside.
Super cheap, durable, lightweight, custom and EASY!
Cost if you had to buy everything? around $3 -assuming you have a hairdryer, a hot glue gun and plastic wrap
** Mine is still in progress will post more pics later. Keep in mind this is my first mask ever. This one can come out a lot better with the magic that some of you crafters can do. **
Plenty of paper the color of your choosing I bought a pack of colored construction paper from the dollar store
A printout of the design you want
Model or foam head
Hot glue gun
Elastic straps, elastic string, ribbon etc - you can find ribbon at the dollar store but I had to go to the craft store for the elastic
Old towel if using model
Small paint brush for applying the glue
Embellishments or paint
Craft time: will vary I did mine in 4-5 hours not including drying time
Model time 10-20 mins