Boxes.
The size of your box must be determined by what you want to put in it.
Penny goods are packed 50, 72, 100, 144, etc., in a box; five-cent package goods 20, 24, 50, 100 in a box.
Buy your boxes of some local supply.
If that is not possible, buy your boxes flat from the nearest convenient maker and use a Corner Box Stitcher to put them together.
Boxes take up less storage space. You make them up as you need them. Boxes are stronger. Other pop-corn manufacturers find this the best way, so you should investigate the method.