A Christmas gift of paper money is more fun to give when it is folded into the shape of a holiday tree to decorate a package or card. The Origami Resource Center website (see Resources) notes that "money origami" may have begun as early as the 1800s, but didn't become popular until the 1950s. The website provides links to numerous illustrated pages for money folding projects ranging from butterflies and blossoms to the pine tree described here.
Select a crisp bill. Fold it in half lengthwise with the Queen's face side inside the fold. Unfold it and lay it flat.
Fold the bill in half again but in the other direction (face still inside fold) with the short ends lined up and the reverse side of the note facing up.
Fold down the reverse side part way, creasing it horizontally.
Turn down the two top corners of the last fold, forming tiny right triangles separated by a 2.5 cm (1 inch) space.
Begin creating the tree trunk by folding the lower left corner of the note toward the right, letting the right triangle turn into a roof-shaped triangle. Repeat this process on the right side of the bill. The fold from step 3 now is divided into thirds vertically.
Make another set of triangles. Start at the midpoint of the note's top edge to fold down the top two corners until they touch. Start at the midpoint of the note's top edge. This is the beginning of the tree's peak. The note's shape now is similar to the spade on a playing card.
Transform the spade into a pine tree by folding two more long, shallow triangles stretching from the peak of the tree to the bottom right and left corners of the spade. Flip the folded note over to see the tree, then tape it to a package or card.