I got it from here: http://www.origami-instructions.com/
I'm not good enough at origami to make most of the stuff on the website, but the bag is easy and really cute!
Start with a square, then fold in half into a triangle.
Fold the point down to make a crease, then unfold.
Fold the two points on the sides in so that the edge is in line with the crease, it should look like a pentagon.
Fold in half so that the side with the folds is out, it should be the same on both sides.
Make a cut in the top from the CLOSED SIDE, I like cutting a half triangle, but a half circle could work.
Unfold, then tape the edges down.
You can put coins, erasers, and other small things in this. It is also nice to put some chocolate in and give it to somebody :). Send me pictures of your finished bag, I'd love to see them!
Note: if you want to add stripes or polka dots like I did, you only have to draw it on one side of the paper.