I usually manage to feed the 3 of us on $15 a day. I buy a lot of bent and dent, Save A Lot (like Tesco I think), generic brands, shop the sales and markdowns, eat soups, sandwiches, stockpile, etc. Just tonight I picked up 4 boxes of bent and dent with 14 - 16 items in a box for $4 each. The box I opened had 3 cans of artichoke hearts, which run $2.79 each, so I made out like a bandit. The average price per can of the items in the box is 35 cents, which is dirt cheap. I also shop at Sams for bread, lettuce, and soy milk. Significant savings on these things there.
A friends daughter doesn't eat hot dogs buns, but eats the hot dogs. At bowling she gives me the hot dog buns. She gave me her turkey carcass from Thanksgiving. That yielded 2 bags for pasta and enough stock and meat on the bones to make a turkey pot pie.