Change of Heart
This is a fun money fold. I understand that the name of the design is "Flower Heart" and it was designed by Kathleen Weller. There are some diagrams available on line, try Origami Resource Center for starters.
I've photographed each of the steps and posted them here. Follow the instructions, duplicate the images and you should be able to create this model fairly easily. Good luck and happy folding.
Note: You can do money folds with any denomination and age bill. But, while it isn't "required" that the bills be new, the finished model will look better, and perhaps more importantly, folding the model will be easier with new bills. A new, crisp uncirculated one Dollar bill will just "pop" on many of the folds. I go into the bank with a fancy fold (like a peacock) and ask if they can check the vault for uncirculated bills.
1. Start with the dollar (bill) face up. Fold the upper left hand corner over so the short side of the dollar lies along the bottom edge. Line the edges up, so they are even. (You are making a valley fold.) This will form a triangle. Crease the bill at the fold. Once you've made the crease, unfold the bill.
2. Now fold the lower left hand corner over so the short side of the bill lies along the upper edge. Line the edges up, so they are even. (You are making a valley fold.) This will form a triangle. Crease the bill at the fold. Once you've made the crease, unfold the bill.
3. Turn the bill over to the backside. There's an X crease from the diagonal folds we just made on the left end of the bill. Fold the short end over the back, keeping the upper and lower edges even. You want to make a vertical crease that runs through the center of the diagonal creases we made in steps 1 & 2. (This is a valley fold.) Once you've made the crease, unfold the bill.
4. Look at the back of the bill there are two raised diagonal creases and one sunken vertical crease. Take hold of the raised diagonal creases, let the sunken vertical crease recede to the inside as you match the edge of the diagonal creases, letting a small triangle form.
5. This picture is the face of the bill after you've let the folds close up. This is called a water bomb base. Water bomb base is a starting base for many origami models.
6. You will now repeat steps 1 through 5 on the right end of the bill. Once completed you will have water bomb bases on both ends of your bill.
7. With the bill face up, start on the left end. Take the lower tip of the triangle on the left and bring the tip to the point of the outside edge. (This is a valley fold.) You are forming another triangle. (Be fairly meticulous, the finished piece will be nicer if you manage to keep your edges uniformly even.) When you are satisfied with your position, crease at the fold.
7a. You will now, repeat this step on the other three triangle points. (The one above on the left and the two points on the triangle on the right.) The picture shows all four points folded.
8. Insert your finger tip, or a toothpick if need be, and separate the two layers of the points you just folded. You will see the seam of the layers beneath. Line the crease that runs through the point of the upper layer along the seam of the folds beneath, (see picture 8a). The edges of the triangle you had formed will spread to either side (making a square), crease the edges of the newly formed square. (These are mountain folds. This is also referred to as a squash fold.)
8a. Make sure you look at the pictures if you are uncertain of the directions. Repeat the squash folds (as described above) on the other three points.
8b. When you have successfully completed the four squash folds, you'll have four squares on the face of you bill. See photo.
9. (This next step is the first for making a fold which is called a sink fold, in origami parlance.) Fold the outside point on the left in toward the center of the bill until the point reaches the edge of the line formed by the edges of the squares you made in the previous steps. When you have the paper positioned properly, crease at the fold. (This is a valley fold.) Crease this fold good and hard, you'll need to see the crease marks in the steps ahead.
9a. Repeat the step above on the right end. See photo.
9b. Unfold the left end all the way back to Step 4.
9c. Look at the back of the bill. There's a square (which was formed when you creased the outside point) which I've marked over in the photo to allow you to see it better. The center of the X from the diagonals we made and the vertical crease which bisects the X are all inside the square we just made.
9d. Reinforce (pinch the bill along the lines of the square) the edges of the square. (These creases are mountain folds.) Doing this allows you to better see where you're working and it helps encourage the paper to collapse where you want in the steps ahead.
9e. The square will stand away from the surface, as you fold the paper around, down.
9f. Hold the bill by the diagonals which you folded in the first two steps, with the square standing in the center.
9g. Use your finger tip and push the middle of the square down a bit. Push in along the edge sides of the square between the top and bottom layers of the bill.
9h. The bill will collapse along the diagonal and vertical folds we made in the first three steps. Continue to coax the paper to close.
9i. As the paper closes on these folds the square will close up to the inside. This is a completed sink fold. Repeat all parts of Step 9 on the right end.
10. Once you've completed the sink folds as described above, refold the small squares we had created in Step 8. See photo.
11. Starting on the left, take the edge of the square, fold the two layers of the paper over, forming a point at the center (the open end of the square) and lining the open edge of the paper along the center diagonal crease. When you've got the paper positioned to your satisfaction, crease the fold. (This is also a valley fold.) See photo.
11a. Repeat this on the other edge of this square. You will see they look like little kites.
11b. Repeat this step on the other three squares. See photo.
12. Using your toothpick, again, or your fingernail, spread the two layers of the paper apart. Much as we did in Step 8, we're going to make a squash fold here. Line the crease from the outside upper edge up with the seam of the paper beneath, the paper will spread to either side of the crease. It will look like a diamond shape, make new creases at the folds. (These are mountain folds.)
12a. This is a squash fold completed on one edge. You will repeat this seven more times.
12b. This is how the face looks when all the squash folds have been completed.
13. Fold the bill in half, making sure to match the outside edges. Crease along the center fold. (This is a valley fold.)
14. Fold the right edge back, just enough to reveal the left side. Make sure you don't leave a gap in the center. But don't let the right side, overlap the left, either. Crease the bill once you've positioned it properly. There's a flower (or star) now visible in the center.
15. Flip the model over to the back.
15a. There's a small flap which sticks up above the edge of the model. Fold the flap back along the line of the edge of the model. See photo. (This is a valley fold.) It will form a small triangle.
16. Fold the back layer of the model down as far as the paper will allow.
16a. It will look strongly like a heart at this point. Smooth the paper along the crease.
17. There is a small flap sticking out along the bottom edge. Fold the flap over the back of the model, maintaining the outside edge of the model. (This is a valley fold.) It will form a small triangle.
17a. Lift the edge of the paper revealing the layers along the bottom edge of the model, tuck the triangle into the space between the layers. This will lock the front and back of the model.
18. This is a completed model.
18a. To add a coin, slip the coin under one of the points in the flower (star) center.
18b. Every other point will lift, move the next point over the coin.
18c. There will be four points over the coin when you've finished seating it, in the model. This is a completed model with change.