DYI Stencil Set for UX design

I’d like to have my own stencil set to make UI/UX sketches. Here’s what i found in an art shop in Lucca.

Simple plastic sheet and a precision cutter.

I’m going to have something like this  http://cdn.shopify.com/s/files/1/0042/9602/products/big.jpg?101250

Or this http://cdn.shopify.com/s/files/1/0042/9602/products/iPhone_stencil-8.jpg?101250