I finally got around to trying a Card in a Box! I used the Serene Stamper's tutorial and youtube video that I found on here on Pinterest and for the most part had little problem. My friends Cari and Jannah reminded me "it's just paper" when I was feeling a little unsure about the cuts to make, so go ahead and try it! My advice is just make sure you use Sticky Strip for adhering the sides together and as much snail as you can to stick the flowers down.
A lot of people have asked about how to mail this. This is a picture of what the card looks like folded up. Since every card will be a different size based on your placement of flowers (or whatever else you choose to go inside your box), I would suggest using the Envelope Punch Board to make the appropriate sized envelope. This tool makes envelopes in 66 sizes! Check out the video to see how it works!