http://strongstamps.blogspot.com/2010/05/star-box-with-note-cards.html I used posterboard for my box and increased the size just slightly. It hold a set of 6 cards and envelopes. My cards were lumpy and bumpy but do fit in the box.
The paisley stamps are Michael Strong Designs and the sequin waste looking background stamp is from Cornish Heritage Farms. I went with a ribbon tie rather than the narrow cardstock sleeve Michael used. It just seemed right for this box.