Past couple of years, every time we use a can of something, I buy two cans (more if on sale) to replace it. Also, a side benefit to our recent healthier eating habits means that the canned stockpile is building up.
Our local survival outfit
http://www.majorsurplus.com/RetailStore.aspx occasionally has sales on bulk MRE's, Mountain House, etc. for cheaper than one can put together meals from the grocery store.
Before Easter, one of our local stores offered a free frozen turkey for every $150 spent. We spent just over $300, so got two. My 85 year old Mom, who keeps about three days' worth of food on hand (her market is only a block away), got one turkey to 'store for us' in her freezer. Little does she know that stuff we put in her freezer along with a bunch of canned goods/water we store in her garage is her personal emergency supply.
I've never paid much attention to our local dollar store and didn't know what kind of food they had. It's right next to the place I get my hair cut so I stopped in last Saturday. Del Monte corn two cans for a buck? Cup-O-Soup four for a buck? I had to ditch the little hand basket for a cart. We may not even have to eat the cat in a disaster. Her favorite dry food was on sale for ~30% of what I usually pay for it.
Unfortunately, I can go nuts on something that's not really that great of a deal. My Wife is the coupon queen, so I often give her a call when I'm in a store to make sure I'm not paying too much for an item.