My 7 year old son wanted to be Optimus Prime this year, and I embraced the challenge! We used cardboard boxes and made several trips back to the store for “just one more roll” of duct tape. Coffee can lids make up the wheels, and square tissue boxes fit his legs perfectly. Flashlights from the dollar store were great for working headlights.
It took a few hours a night over 2 weeks to complete it, and he couldn’t be a happier Transformer. He even won first place for his age group at the local Golf Course Halloween party!