i would hedge on ammo cans being the next item of need, they are fairly common and cheap for the durability and water proof rodent proof storage of food items, things you want to isolate from contamination such as facemasks air/water filters firstaid/ adv.firstaid kits, masonjars full of food etc.
5 gallon buckets with a screw-on lid are great for that, too. Probably not as rodent-proof as the ammo box, but I haven't seen any rodent damage on mine yet.
