An initial investment in food can be a huge sack of beans and a huge sack of rice stored in airtight containers. Eat it and replace near the end of it's lifespan.

Cheap as can be, light compared to cans. Water can be stored separately and then is free to use for other purposes if needed.

Every try to flush the toilet using canned stew? Wash a wound with cling peaches? Bathing in a tub of water chestnuts?