I've posted a similar type box in the past. It's made with two scallop envelope diecuts and two 2-1/4" x 1-1/2" strips of card stock for the sides. The notecards are 3" x 3" (3" x 6" card stock folded in half).
Stamps: Fox & Friends & Tiny Tags (both from the Stampin' Up! Occasions Mini Catalog)
Accessories: Sweet Pea Designer Paper PAD, Corduroy button, Linen Thread, Jewelry Tag Punch, 1/16" Circle Punch, Big Shot, Scallop Envelope Die.
If you live in the San Antonio area and would like to get a few of your friends together to make this super sweet gift set, give me a call to schedule your own private class (at your house or mine).