I really enjoyed the original gift box that sneakypoo created (https://www.thingiverse.com/thing:201097), but wanted a smaller version with the possibility as a key chain. I shrank it by 50 percent of the height and modified to fit while adding an optional lid with a key ring.
It held my US dollar nicely when quartered and rolled (fold in half and then in half again and roll it up).
Used the original thing and modified in Windows 3D Builder
I imported the parent project into Windows 3D Builder and resized it and added a key ring. I had to modify the button on the lid a little bit as well to form a nicer click when fully sealed up.