We take the packaging from a lot of food and drink products and use that to print greeting cards with various sayings. We've done some Valentine's Day cards using any packaging that connects with anything chocolate.
The A2 cards fold to 5.5" x 4.125" and come with envelopes. We sold about 3,000 of them through stores, but slowly we lost interest in trying to keep up with the card market. They are fun to print, but they aren't what we get up in the morning to do.
Boxcards are the exception. We have some friends that bring us their packaging, and we love the idea that they have a spot in their kitchen where they keep them until they get enough to warrant driving them over to our studio. Recently a friend from Lancaster, PA dropped off the packaging from 50 cases of Yuengling which we love the colors.