Just stock up as you go-you'll be surprised how fast items pile up.
When King Soopers had a recent sale on canned veggies I stocked up on what we eat (don't buy what you don't usually eat) at .50 a can.,2 for 1 sales, Mgrs. specials on meat etc. vac seal and freeze. I spent a lot of years camping and hunting so I have a good source of stoves,lights etc. Just stock up on fuels.
It's a lot easier than folks make it-Good Luck