I don't know how many or who stores back an extra food supply but I stumbled onto the Mormon store while looking for canned flour, there is absolutely no one that can approach their price on canned long life staples like flour, whole wheat flour, rice, oatmeal dried pinto beans all packaged for long life in # 10 cans sold in cases of 6 for 28.00 -35.00 per case depending on product, their shipping is free and you need not be a church member you just sign up as a store member or use guest checkout.
http://store.lds.org/webapp/wcs/stor...57345616897723

For peanut butter, Tuna and many other canned products I use Amazon, sign up for Amazon prime and you will save a bundle if you stick with Amazon prime Items.