I commend you on your ambition. But building a humidor is not the "cheap" way to go. You can get a decent humidor for $40-60 online, while building one will cost more just for materials. If you have access to good woodworking tools then at least that cost can be avoided. Recycling old boxes seems very impractical as you will have different thicknesses and sizes of wood. But good luck and please post pictures.
