I created this Homemade Optimus Prime Costume out of boxes and duck tape! I had to measure my son to get his dimensions right then I made the wheels on his thighs by cutting out a 5 inch circle then gluing it to a strip of cardboard long enough to go around the whole circle and about 3 inches wide to make it look like a real fat tire. I then cut another 5 inch circle and glued it on the open side to close the wheel.
The shoulders have tiny portable lights I found at the Dollar store they look great in the dark. The flames I drew myself on a cardboard then cut it out and used it as a stencil for the rest of the costume. All the tubes you see are the cardboard tubes that come inside of aluminum foil when the roll is gone. The helmet is made of paper mache which is just newspaper and a mix of 2 cups flour and 2 cups water. The bottom belt part with the logo is made easily. I traced it from a picture online and behind it, I just covered the cardboard with some left over patio screen material, (it was really just a scrap peice). The rest is just spray paint. Underneath it all he is wearing silver long-sleeved shirt and pants to give the robot look.