Sure,  a 3d-printed case for gridfinity is nice and beautiful. But it uses a significant amount of filament. And many of us store things that we might use once-in-a-blue-moon.

If you shop at Costo, chances are you have seen these containers.  They are used in a variety of products (they measure 220x220 mm with variable height, the short is 60mm and the tall is 100mm)

These containers are great:

1. They are relatively strong
2. Their lid closes nicely (it is not too difficult to open, but it will not open by accident--usually)
3. They are transparent
4. They are stackable
5. And more importantly, they are free

With these base grids and lid you can turn them into decent carrying cases for gridfinity. The lids close securely and are practical even for transportation.

Unless you plan to shake them (or you carry very small things in a bin) they will keep things in place, even if you don't use the gridfinity lid I provide. 

If you don't use the lid, you can see what the (top) bins have.

The small case (Aussie bites) is 7 units high, and the Madeleine is 13 units high.  It assumes the bins have the “lip for stackability”.

The only reason to print a gridfinity “lid” is if you want to carry small things and are worried that they will spill from one bin to another. Otherwise only print the base grid.

Choose the base grid accordingly. The “lid” is compatible with both sizes.