This portable box is easy to print and simple. I made this because I wanted a place to keep cash and quarters at work for the vending machines. I find this can also hold rounds and other small/foldable objects. The outer box has a slot to push the container open with your thumb.

The locking pin can be printed standing up but for durability I printed it sideways. Two secondary locking pins can go through the holes on the primary one to secure it even better but I find just the one normally does the trick. (These two secondary pins are for if your printer isn't too good with tolerances-- the one pin should hold just fine if your tolerances are good.)

Inner dimensions of the container are as follows:

2.180 (55.37 mm) wide

0.480 (12.19 mm) tall

3.418 (86.817 mm) deep