A little late...but, here's the project we did at the Ben Franklin paper party this past Saturday:
The idea is from Jenny, the store manager at Ben Franklin (Mapunapuna). Thanks for the idea and fun time, Jenny!! To make this envelope...start with a sealed envelope. You can make it into any size you want by adjusting the length of the top and bottom piece. I used a decorative edged scissors:
Stamp and decorate as desired, then crimp the bottom portion only (note the direction of the crimpng). Crimping shrinks the bottom portion enough to fit back into the top portion.
Hope you have time to try this...you can make it small enough to hold a gift card...or large enough to fit a gift of money.