A box and gift bag, from a single uncut silver rectangle (A4 / A5 or larger).
This is a really simple model which is very quick to fold. Like my triangular flat pack box, the bag will fold flat.
The models in the photographs were folded from A5 iridescent paper. I recommend at least A4 size if you want to use the box or bag for gift. The bag will lock shut without tape or glue. You could also experiment and fold with a differently proportioned rectangle (but it won’t work from a square).
This model will work with just about any paper. Try one from any A4 you have around including junk mail. Wrapping paper will also work well if you have a larger gift you want to wrap. The paper I used is not suitable for most origami as it doesn’t hold a crease well, but it holds up for this.