For our catapult we tried as hard as we could to use all recycled materials, but unfortunately we couldn't find some materials such as wheels. This is our list of materials that we used in our catapult:
Wood - $0 (found in the shed)
Screws - $0 (in Mr. Sevilla's classroom)
Wheels - $5 (bought new from home depot)
Hinge - $0 (found in the shed)
Rope - $0 (found in my house)
Bungee cord - $0 (Preston brought from his house)
Ball holder - $0 (Recycled package)
Wood - $0 (found in the shed)
Screws - $0 (in Mr. Sevilla's classroom)
Wheels - $5 (bought new from home depot)
Hinge - $0 (found in the shed)
Rope - $0 (found in my house)
Bungee cord - $0 (Preston brought from his house)
Ball holder - $0 (Recycled package)