As of last night, I have sold 50 boxed sets of Giggle Greeting cards (at $6 a box). Each box contains four 3 by 3" cards and envelopes. The cards are blank inside, and each person who buys a box is warned that the cards are too small to go in the mail. The box itself is made using the Envelope Punch board, has progressed to having a window in it and is decorated. I am now in the process of making 4 more boxes for my next several craft shows.
Here's what they look like.
This is the original box, but I progressed to the one with the oval window in it. Check out the tutorial for making window boxes for the magnets I make.