Why put money in the pockets of food stores when hundreds of dollars a year can be saved by becoming a smart consumer?
Make a permanent list of staples to use as a checklist.
A permanent list of items that are usually purchased can be checked against the flyers that are sent out by major groceries stores.  Watch for such things as "Buy one, get one free" items however only purchase those  you normally use. 
Using Club Cards
Most groceries stores offer "Club Cards" or "VIP Cards which are provided free to customers. During one weekend, one store offered beef round steaks for $1.77 a pound, a savings of $3.22 over the retail price.  Another store had lean ground beef at $1.88 a pound with a club card, $3.49 a pound without one.
Buying by the carton
If you use enough of a product, ask if there is a discount when you buy a carton at a time. This can amount to a savings of 10% or more.
Watch for "sell dates"
Look at sell dates carefully, making sure that there is enough shelf life remaining .  If it has been marked down and you are planning to use it immediately, take advantage of the bargain.  Fruits can be cooked or used in pies or tarts.  Vegetables that look a little tired can be used to make soup.
Buying store brands
At one time, store brand groceries were of inferior quality but this has changed recently.  Compare ingredients with brand names.
Salvage supermarkets
Items that have been discontinued by manufacturers or are improperly labeled, dented or about to expire are discounted as much as 50%.  These stores are usually inspected by state officials and meet the same safety requirements criteria as other supermarkets.  A state-by-state list of salvage supermarks can be found at http://www.frugalvillage.com/forums/showthread.php?t=97055
Dollar stores
Many dollar stores carry canned and packaged goods at great savings.  These should be checked carefully before purchasing for broken packaging or bloated cans.
Farmers Markets
Because the middleman---grocery stores---are cut out of the pricing structure, farmers markets offer products, especially produce, at a lower cost than can be found in supermarkets.  In addition, in-season produce is usually fresher and will last longer because it has not been shipped in from another part of the country.
Cooperative buying groups
Food co-ops offer natural and organic food at lower prices than can be found in supermarkets. Some trade service which can be exchanged for products.
Internet shopping
Many items can be purchased at lower cost on the internet however watch for shipping and handling charges because any saving may be lost when these are added.
A few other hints
Eat less meat or buy the cheaper cuts Avoid out-of-season produce Watch for marketed down or closed out items Coupons can create savings if only used for items usually purchased Cut back on buying plastic bags and wraps for storage; use washable containers instead.
More articles about food shopping and preparation

http://healthycooking.suite101.com/article.cfm/fruits_vegetables_safe_to_eat
http://consumereducation.suite101.com/article.cfm/quick_and_easy_ways_to_save_money_on_food