You'll love seeing their face go through the emotions: curiosity, confusion, disbelief, and finally, laughter. A very cute gift, it can be made entirely of money. A money box opens up to reveal a money shirt, complete with a tag saying 'XXXXXXXS'.

Step 1: Materials

2 Crisp dollar bills, or just pieces of paper cut to $bill size.
String
Small piece of paper

WHAT?!?!?! That's it?!?!? Yes, it's true. This will probably be the cheapest, funniest gift you will ever give.

Tools:

pencil
ruler

Step 2: Make the Shirt

Crease everything well.

Fold your dollar bill in half lengthwise.
Fold the top corners to the middle.
Fold the whole triangle down.
Use a pencil and ruler to draw the shape of your tie. You can make it however you want, but not too skinny or else it won't work.
Unfold the triangle. Fold along the lines you've just made.
Fold the triangle back down. Fold the tie in half, bringing one side of the tie to the other. Flatten the top when it follows.
When you unfold the tie again, it should stick out.
Repeat 6 and 7 for the other side.
Fold the left and right edges to meet the center as shown.
Unfold one of the folds you just made. Redo it, this time making the marked corners meet each other. This will take some fussing, but you'll get it right eventually.
Repeat on the other side. Fold the bottom of the paper up about 1/4 in.
Turn the paper over. Fold the bottom corners in at an angle to meet the center. This is your collar.
Turn the paper back over. Fold the bottom up so that there's 1/8 in between the bottom of the tie and the collar.
Undo this fold. Redo it, pulling out the middle as you go. When you flatten it again, there should be 'sleeves'. If you want bigger or smaller sleeves, pull or push on them gently and flatten.
Turn the paper over. Fold the whole thing in half as shown.
Fold up the collar so that it peeks over the top of the shirt.
Turn it over and hook the collar on the shirt.

Step 3: Adding the Tag

Get your pencil. On your small slip of paper, write XXXXXS with a lot of X's. Leave a little space on one end.
Poke a hole in the space you left on the end with your pencil. Erase any marks you made.
Poke a hole in your shirt wherever you think a tag is put. Erase any marks you made.
Thread the string through each hole and tie it.
:) Cute!

Step 4: Make the Box

Make sure you start with the right orientation. You really need to see the pics for this one. I put HARD! next to steps you need to be careful with, they're HARD!!!

Fold your dollar in half hamburger. Unfold.
Fold the left margin in as shown.
Fold the top and bottom margins in
Fold them in again. Be sure the top and bottom margins are even, or else your box will end up lopsided.
Fold the left side up till the edge of Washington. While doing this, pull the edges out to form the fold shown. Crease everything down. HARD!
Pull the bottom edges out while pushing the top edges back in, and crease the corner. HARD!
Take your pencil and slide it (eraser end first) in the hole. Push against the little flap thing (shown) and crease everything around it. I fussed with this for a LONG time before I got it looking just right. Make sure you crease everything well to give it the best boxy shape. HARD HARD HARD!!!!! The are several pictures for this one.
Slide the shirt in. The sleeves will not fit, so fold them behind.
Make a mental note of where the bottom of the shirt ends and take it out. Fold the end over on that place.
Push in the top edges like you did in step 5. Also, keep the bottom edges up. Make the same kind of corners as step 5. HARD!
To close the box, fold down the flap you just made and then fold down the other flap and tuck in the edges. Done! Nice!

Step 5: Finishing Touches and Variations

Put the shirt in the box with its sleeves folded back. To open, either lift the top flap or slide out the inside flap and slide out the shirt.

You can add ribbon, bows, etc, or leave it plain.
The instructions I used for the box said that you could change the shape of the box easily, but I haven't tried. You could put different objects in the box if you alter the shape.
If you make a dollar bill ring, you could make a very cheap engagement ring, complete with a matching box.
If you want a full outfit, there are origami pants. just fold a dollar bill into fourths lengthwise, fold in half, and fold in half again at an angle.
When presenting the present, you're gonna need to help them open it. Just don't open it for them.
The instructions I used for the box said an Ipod shuffle would fit perfectly in it.