I have made some of these can rotators using leftover cardboard boxes and empty boxes from the liquor store. Each holds 9-12 cans of various sizes of store-bought beans, fruit, etc. that are part of my typical diet. Not a ton of additional food but every bit helps, and it's a good way to benefit from buy-1-get-1-free sales.

http://foodstoragemadeeasy.net/2009/02/16/build-your-own-can-rotating-rack/

(A hot glue gun makes quick work of this project, btw.)