This birthday card also has a secret "gift card" holder, lol. When you open it up, you will see the gift card nestled inside. I used some chipboard elements to hold the gift card in place. When you remove the gift card you can see the sentiment. The best part about this approach is you can use any embellishment, pop them off the page and there you have a place to rest your gift card. One more tip: I put the tiniest dab of removable tape to hold it in place.
I hope you have a wonderful day!