Costco sells buckets of emergency food with 20ish year shelf lives. I think at one point they had a year-long supply bundle available, best I can find now is 1-month (for one person) at $114 (though it's out of stock).
https://www.costco.com/all-emergency-food.html
So, if/when that's back in stock, $114 x 12 x (# of people in household) is your price for a year of food. Can probably go a little lower if you allow for some lower-calorie rationing (1800 instead of 2000 will probably keep everyone alive and fairly healthy, if not thriving, and for some people might still be more than sufficient). Might want some multivitamins or something, too.
Though you've gotta figure out something for water, separately.
I guess maybe then you eat a month of it per non-emergency year and buy another month's worth every year, to rotate through the supply well before the expiration but while maintaining (about) 1-year's supply of food at all times. That way you're not just wasting the money by putting the food on a shelf until it goes bad, and you're never eating food that's very close to its expiration date. Unclear whether the food's healthy enough that eating it for 1/12 of all meals in a year, indefinitely, wouldn't cause noticeable harm versus whatever diet it's replacing. Or whether it's tolerable enough to eat in a non-emergency situation that you'd be able to convince all the other members of your household to commit to a plan like that :-)