Here's something I put together this weekend to hold a little gift. I made it out of a 12x12 piece of double-sided decorative paper from Rusty Pickle. I also used a small tea doily, a snowflake charm, a stamp by Studio G (J's $1 stamp) and my Spellbinders Nestabilities Petite Scalloped Circles dies.
I made a rough template for you to use if you like. You can find it at the bottom of this post. Download and print it off to use as a pattern. Cut on the outside edges. If you want to use your circle punch, I cut the top flap it in a rough rectangle and then stuck the rectangle so only the part I wanted to cut was in the punch. The rest I wrapped to the backside where it wouldn't get cut when I ran it through the Wizard.
Crease one direction on the darker lines and the 2 lighter lines crease the other direction. This photo Shows what it looks like once you cut and fold it.
Use some glue strips to glue the bottom pieces together then glue down the side, making sure to tuck the small 1/2" end underneath the larger side so it doesn't show. The side ends will pinch closed like a lunch bag now. If you like you can glue a pretty doily onto the inside of the flap so just the edge shows when the bag is closed. Use whatever you like to seal it. I stuck the circle medallion down with some glue dots and then I can tuck the scalloped top edge underneath to close it and reopen as needed.