I made the card out of cardstock and punched the edges with a Fiskar's border punch (Border Rope). Then I added stickers and 3D attachments. Once the card is decorated it folds flat and easily fits in an envelope.
This is a second version of the pop up card. I punched out the shamrocks using my Sizzix and I did the border punching with a Martha Stewart edge punch (Embossed Zig Zag). The rest of the decorations are purchased 3D's.