This is getting good.
If you ask around, you should be able to find 50-lb or even 100-lb sacks of wheat berries or whole wheat. You will need a grinder to grind it up into a flour (or a mortar and pestle, if you have nothing else to do), and prices vary because the major expense is in transportation, but it will store indefinitely. (Once it's ground it will have to be used immediately, or refrigerated). Bulgur makes a great easy-to-prepare breakfast, and there's nothing wrong with sourdough. You should be able to find a decent grain grinder for under $100.
Canned food lasts a while, but they don't last forever. Buy stuff you are comfortable eating now, and rotate your stocks using the oldest stuff first. We use a laundry marking pen to mark each can with the month and year it was purchased. It's been my observation that cans with those pull-top lids tend to go bad the quickest.
Onward and upward,
airforce