I learned the "stock-up" technique about five years ago. I only seriously got into it about three years ago. The reason for stock-up is so that you aren't held hostage when prices are high--read anything other than their very lowest.
For example, I don't drink soda, but we keep it on hand for guests and workmen and my parents drink it with cocktails. SO, you can buy coke ON SALE for 2 12-can cases for $8 or you can wait and buy it for 4 cases for $9. When it goes on sale for 4/$9, I buy 12 cases and forget about it for a year. When Harris Teeter has frozen chicken buy 1/get 2 free, I buy it for emergencies. We usually eat organic, but in an emergency, you can't be picky. Toilet paper? OH MY! I have cases and cases in the attic, bought at 12 double rolls for $4 apiece, thanks to CVS Extra bucks. That's $8 for 24 double or 48 single, which costs up to $14 ON SALE now. Yes, it says one per household, but if you know what you're doing...
Get multiple store cards NOW--one for each member of the family. (It all depends on what you call a member of the family.) When they go to rationing, they may ration by card. They already sale ration by card.
I am really pushing you guys to learn how to do all these things--combine coupons and sales and instant money rebates from CVS/Walgreens so that you don't pay top dollar. I never, EVER buy anything at full retail price--except for an occasional treat or something required by a recipe. If it doesn't hit the fan in full blow-out fashion, you can save a TON of money doing these things. After awhile, you know prices off the top of your head, and you can spot the loss leaders a mile away. The sale items usually run in rotation of one month or three months. You can learn this by osmosis depending on your store. Just take an hour a week to study the ads, group your shopping so that you don't waste gas, visit each store no more than once per week, and be sure to shop Walgreens only on Friday or Saturday when you can use the Internet coupon for $5 off $20 or $10 off $40 in addition to sales and manufacturers coupons. BTW, you can always combine Walgreens coupons with manufacturers' coupons.
Depending on your climate, during the winter, you can use your attic for storage of things that you might otherwise refrigerate--not necessarily freeze--nuts, vacuum sealed cheese, etc. During the summer, you can live off produce.