In general, none of us are
survivalists in the style that main-media portrays crazies like those in
Waco or
TimMcVeigh.
What you will find here are people who realize that they are responsible for themselves, their families, and that waiting for government or military or (fill in your blank) to take care of you is not a viable option.
Now - go get to an answer of your original posting, what many of us will do is slowly double our grocery purchases. If you like rice, instead of buying a small thing of "UncleBen's", get a rice-cooker (relatively inexpensive) and a 50-pound bag of rice for $15.
If you like spagetti, instead of getting a small "single-meal" container of noodles, purchase in "restaraunt-sized" bulk containers.
I personally can't afford to drop a grand on food in one month with my other bills, but, I can afford to drop an extra $150 to $300 in a month on extra food-stocks. The easiest thing to do is to build a giant pantry in the basement with lots of shelves and floor space and take your time filling it up. Mark all the cans / boxes / bags with their "best-before-date" and use them by that date and put the newest stuff at the back - rotating the foods forward.
Also, consider water-cooler style bottles and rotate 10 (or more) bottles worth of water. You can also plumb-in a cold-water tank (similar hook-up as a hotwater tank but without the heater) with a flow-control regulator (so that the water in the
house does not flow back into the main pipes).
In my house, I have a section in the basement for food supplies. In that area, I have cupboards with doors for dry-goods. I have shelves attached to the walls for jar-goods. I have free-standing tin-shelves for metal-canned goods. I have my large deep-freezer in that area as well for all my frozen goods and, because the walls are not "finished" in that area, I use the area between the 2x4's for "mini-shelves" for items like my 2lb propane bottles, bulk-spices and noodle-soup-packs.