I used a textured white core cardstock, but any good quality card would do.
I've just realised that I've missed a couple of measurements off the template - the width is 2" (but it extends to 3" for the bottom part as shown). The two side flaps at the bottom measure 1/2" wide each (so the flaps are three and half inch long by a half inch wide). Sorry about that, but please don't hesitate to ask me if anything is still unclear.
To make the front a little more interesting, I textured it with my Big Shot die cutting machine using a Cuttlebug embossing folder.
I did a bit of rubber stamping inside and out.