Hi there. I fit 3 x 20L feed bags in an unused 240L recycling bin. It had wheels but sits under the verandah. My daily implements, supplements and scoops etc also sit inside this.
More rarely used items such as medication are shelved in the house.
My straw bale is in a large metal drum with metal lid and stays dry inside. It sits on concrete outside in the weather next to my garbage bins. While it may rust, I can see and replace it if needed. At the moment it has lasted several years with no rust apparent and no infiltration- I love it.