Places like Target, Home Depot, Costco, etc... have all shapes and sizes of containers that are well suited for making humidors. I wouldn't sweat it too much on how air tight it is. Actually, a little leakage is preferred. As far as putting Spanish cedar in it is your call. Makes it smell nice. I generally just put the boxes in the coolerdor with a bunch of beads. Buy twice the amount of beads that they say. There are some good wooden starter humidors on this site. If you need some empty boxes let me know and I can set you up. YMMV