Sketch Pad for Smartphone and Web App Design

The pad help designers and creators capture the essence of an idea at the very start of the iteration process. I use pads to create first sketches of apps, and in the process, I waste a lot of paper. The average price for a sketch pad is around $15-20, and having a reusable one would be cool. I believe that designers and product managers can benefit from reusable sketch pads.