Today I'm sharing a card I made last month for a friend. I can show it now as her birthday was last week.
A card in a box using the Party Pants SAB stamp set, now retired. Some of the balloons are covered in Crystal Effects to give shine. I've added glittery glimmer paper stars and also a greeting which comes from Suite Sayings. The DSP , which works perfectly, is Birthday Bouquet Designer Series Paper and has multiple balloons all over. However, quite a few of the sheets in this pack would have worked well on this card.
Although quite decorative, this card is pretty sturdy and stood up to being mailed to Canada - phew!
Card in a box may be a little more time consuming to make but the effect packs a punch when the receiver opens the envelope, which is exactly what you're aiming for!