This minion cost about $6 to make. I used white poster board, hot glue, foam, felt, and jean. I made this for my son, he also wanted to be Sonic which you can find on this site too. The Sonic took my awhile, this costume only took a couple days and I let it dry overnight before decorating it. www.JJsHalloweenOutlet.com
I used plastic chicken wire to make a form for the paper mache head. It would be easier to just use a large balloon. I used about 5 layers and let it dry over night. I then glued and taped white poster board to form the body. I cut the arm holes and let my son try it on. I ended up paper macheing the entire thing because the post board just wasn't strong enough. Next time I will just use cardboard.