This is a project that Close to my Heart did at Convention in August. I've seen it around but just recently learned out how to do it. It looks difficult and is impressive to your friends, but is REALLY easy!
Cut a background paper 8" x 6". Fold in half both ways.
Fold the two corners down, like so.
Now you have your two compartments for the gift card and a little note :) Use some adhesive to keep the edges together (but be sure you can still fit the gift card and note inside).
Embellish as desired.