If you're more of a acrylic guy, then you take your laser-cutter, cut out some shapes, drill a few holes and bam you've got a box.
If you got none of these and just want a bare-necessities box, you use an Altoids Tin that costs about $25 for 12 tins... and they have these kinda useless mints in them though. So you buy those boxes, then you throw away the mints and shove your project in there.
If you've got a 3d printer, you make a 3d print.
If you're more of a acrylic guy, then you take your laser-cutter, cut out some shapes, drill a few holes and bam you've got a box.
If you got none of these and just want a bare-necessities box, you use an Altoids Tin that costs about $25 for 12 tins... and they have these kinda useless mints in them though. So you buy those boxes, then you throw away the mints and shove your project in there.
If you want slightly better than the Altoids tin, you buy a Hammon Enclosure. (https://www.hammfg.com/electronics/small-case).
If you're like me, you wrap it in electrical tape, and then wrap that in duct tape or something. Maybe color on it with permanent marker.