Cardboard is an inexpensive material, making it highly accessible to educational institutions with limited budgets. It ensures that the benefits of rapid prototyping are not limited to well-funded schools but are available to all.  You can get cardboard from the many packages that schools receive every day.  Local businesses often are happy to give you their cardboard waste.  I get much of my own cardboard from a local beverage store.

Cardboard is eco-friendly, as it can be easily recycled and repurposed. Teaching students about sustainability through cardboard prototyping encourages responsible resource use.