When the going gets tough, the tough hoard half-price specials. They also make trade-offs, outsmart merchandising gimmicks and plan ahead. We wanted to see how the "tough" beat the high cost of food in Washington, so we went shopping for a week's worth of groceries with them.

Three budget-conscious consumers, chosen for their differing points of view, not for where they shopped, were each joined in their neighborhood supermarket by this reporter. The purpose was to watch them shop -- and to talk about their food selections, buying patterns and tricks for saving.

It was time. Last week marked the first anniversary of the warehouse and discount pricing wars launched by area chains. Although food prices are still less than they were before the war began, they are edging back up, according to a recent Washington Post survey of 30 of the area's most frequently purchased items. And this summer, despite the lower prices precipitated by the price competition, an annual newspaper food editors' survey found the cost of food in the District to be higher than in any other city in the continental U.S.

Our price-savvy shoppers came from government (Diane Odland, a U.S. Department of Agriculture home economist with a family of four), the public (Charles and Sara Sklar, a retired couple from Takoma Park, who have made bargain hopping part of their daily routine) and industry (Odonna Mathews, vice president of consumer affairs for Giant Food, who gets employe discounts only on prescription drugs).

While each approached the shopping experience with a different bias, they all demonstrated the point that good food-money management doesn't necessarily mean ransacking the supermarket for deals. It means taking into consideration family food preferences and needs, and being flexible enough to juggle meals when schedules go haywire, instead of throwing things out. They also demonstrated that whether you fill your shopping cart with caviar or corn chips, everyone can probably save money on food bills by simply being more aware.

Here's how they do it.

Shopper: Dianne Odland, USDA. Last week's food bill for family of four: $87.89.

Dianne Odland analyzes a supermarket like Sherlock Holmes unravels a mystery. Equipped with bits and pieces of information, she can solve a buying decision in minutes and recognize a merchandising gimmick on sight. The author of numerous food money management guides -- including cost analyses of salad bars, bulk foods and frozen entrees -- takes control of her shopping, remembering last week's prices, quickly scanning unit prices on a product line or running back to compare item prices in another aisle.

Although it was not the original intent of the trip, during the course of the two-hour shopping spree, the USDA home economist discovered several price errors and confusing labeling in her local Giant:

Three one-pound bags of carrots were on sale for $1. Concerned because the bags didn't feel as if they were filled with equal weights of carrots, Odland weighed two of them. One weighed 1 1/4 pounds, another less than 3/4 pound.

A bonus special sign for a two-pound container of Giant brand cottage cheese listed the unit price as $1.69 a pound. On the same sign, the cost of the two-pound container was listed as $1.69.

Unless you carry a calculator with you -- and even if you do -- it is difficult to compare the unit prices of frozen juices to their counterparts in cans or jars. That's because the unit price of frozen concentrate is listed per pint of frozen concentrate, not the cost per diluted amount. The unit price of juice in cans or jars, however, is listed per diluted quantity.

Odland says other things sometimes "tick" her off in the supermarket.

She frequently checks under sale tags to compare the cost of the original item to the reduced one and gets annoyed when the original item is only a couple of pennies more. Sometimes she misses having the prices on items because it take more time to compare products during a shopping trip. For instance, on this particular day, Odland had to walk back to the dairy case to check the price of the swiss cheese to see if it was a better bargain than the version at the deli counter.

The efficiency expert's buying philosophy is based on unit pricing, house brands and planned-overs, in which she will get two or three meals out of an ingredient (she bought a ham, for example, which she will use for dinner, sandwiches and then pea soup). She has a rough idea of the week's meal plan before she goes to the store, but is flexible enough should she spot a good sale or think of a dish that can incorporate several products in her cart.

At the produce department, Odland scooped up a bagful of bulk peanuts for 97 cents a pound, pointing to the packaged peanuts a few feet away that were selling for $1.59 a pound. (Odland's bulk foods survey, published in 1986, concluded that the largest savings in bulk, compared to packaged foods, was for national brands, smaller package sizes and herbs and spices. Bulk food items that showed the smallest savings over conventionally-packaged foods included basic, lower-cost products such as flour, sugar, rice and dry beans.

Odland made a similar comparison with a five-ounce package of croutons, a bonus special for 99 cents, or $3.17 a pound. Loose croutons a couple of feet away at the salad bar were selling for $1.99 a pound, or 62 cents for five ounces. (This is one of few examples where the salad bar is a better deal; Odland's 1985 survey showed that sunflower seeds, chow mein noodles, grated cheddar cheese and tuna were also less when purchased at the salad bar. The remaining items ranged from the same price to seven times as much when bought at the salad bar. Celery, carrots, cucumbers, watermelon and yellow onions were among the products that were four to seven times higher there.)

Odland made some other surprising comparisons:

Individually wrapped Giant brand processed American cheese was less expensive per pound than the chain's nonindividually wrapped version.

Items purchased in the service deli are not always more expensive than the same or similar items purchased in the dairy case.

You can pay almost six times as much per pound for popcorn packaged specifically for the microwave. Pillsbury Microwave popcorn, for example, cost $3.03 a pound. Giant brand popcorn costs 53 cents a pound. Odland usually buys the regular and pops it in a paper bag in her microwave.

You can also pay more than twice as much per pound for Sun Maid and house brand raisins packaged in mini-snack boxes as for the same raisins packaged in 15-ounce boxes.

Odland makes trade-offs when she buys. She knows, for example, that preshredded mozzarella is more expensive than a whole slab of cheese, but is willing to pay for the convenience. Premade pizza shells, chopped vegetables and bottled sauce are the ingredients for the family's pizza dinner, which is less expensive than take-out, but more expensive than if she made the crust from scratch. She will buy a few cauliflower florets on the salad bar because her family only likes it raw in salads; a whole head might be less expensive per pound, but it would spoil.

Nutritionally speaking, the USDA home economist said she really buys what she preaches -- "usually." Among her family's vices: caffeine-free soda, tortilla chips and ice cream.

Shoppers: Charles and Sara Sklar. Grocery bill for three-stop shopping trip: $24.91.

Unlike other singles or couples, the Sklars believe in quantity purchasing. They stock up on sales. That's why the basement of their Takoma Park rambler is filled with 30 rolls of Bounty paper towels, a case of Charmin, 14 cans of tunafish, 11 cans of pink salmon, four bottles of Head & Shoulders shampoo and many other assorted items.

The Sklars are the type of conscientious consumers who can tell you the number of sheets in a jumbo roll of Bounty towels (it used to be more than 100, now it's down to about 84), or can rattle off the price of just about any item they buy and what it sold for last week. There are some items that always go on sale, they report -- among them, raisins, tunafish, waxed paper, aluminum foil, plastic wrap and paper towels.

They write both complimentary and critical letters to companies, ask questions of supermarket personnel and will not hesitate to ask a meat manager to split a family pack of chicken legs to get the amount they need. At a community gathering, Sara Sklar once reprimanded a representative of a major chain for never offering half-price specials for fresh produce.

"You either like me or you can't tolerate me," Sara Sklar joked, getting ready for her shopping trip. While their shopping patterns are "haphazard," she said, "there is a method to our madness." The Sklars, both in their early 70s, live in an area ringed by several chains, and they take advantage of all of them. When they take advantage of specials, however, they will not be drawn into a store for other high-ticket items.

Sara Sklar scans the newspaper for sales and the couple may stop off at Snyder's after their water exercise class, or Charlie Sklar will pick up a bargain or two at the Shoppers Food Warehouse after his cup of coffee at McDonald's. If navel oranges are on sale at Magruder's, they might combine that stop with buying a container of Axelrod cottage cheese, their favorite brand. Charlie Sklar was an original founder of the Takoma Park-Silver Spring Co-op, and they still purchase flour, grains and honey there on a regular basis. Fresh fruits and vegetables, the bulk of their diet, are purchased at Shoppers Food Warehouse.

This shopping trip with the Sklars, who have been married for 47 years, began at Shoppers Food Warehouse, where the couple felt garlic heads together, searched for brown spots on zucchini and debated over which register line was shorter.

From there, it was on to Dart Drug, where the chain was having a special on Thomas' English Muffins (limit two packages per customer; the couple bought four). Then on to the co-op, where they compared fruit and vegetable prices to Shoppers' and picked up a few more items.

Sara Sklar said she never wastes anything. She will get a few meals from a chicken, toss leftover produce in a quick vegetable soup or use overripe bananas in muffins that she said she bakes for her doctor, neighbors, the mailman or the garbage collector.

Shopper: Odonna Mathews, Giant Food. Last week's grocery bill for family of two: $51.75.

Who else would straighten the bread racks or remember that Giant had a great sale on chickens at the same time "60 Minutes" broadcast its alarming piece on salmonella? (The show didn't affect sales, according to Mathews.)

Shopping with Washington's premier supermarket spokeswoman is a predictable experience. Mathews buys food exclusively at Giant (spying on other chains for research purposes only) and frequently purchases house brands (she knows which manufacturers make most of them).

Mathews and her husband, a physicist with the Naval Research Lab, live in Wheaton and shop in the Giant at Leisure World Plaza. The couple share the shopping and cooking tasks, spending anywhere from $35 to $100 a week on groceries, depending on whether or not they are entertaining.

Before she goes shopping, Mathews makes a list that incorporates ingredients for three or four quick meals during the week. Although Mathews conceded that she is probably more conscious about nutrition and easy meal preparation than she is about price, she follows sales (broccoli and scallops were two of her sale purchases on last week's trip), stocks up on items when they are on special for half price (she bought a slew of low-calorie salad dressings recently), and will wait to buy pricey items until they go on sale (she passed up Head & Shoulders on this trip). Right after the warehouse price war began last September, Mathews said, she did notice a drop in her food bill, but she can't tell whether her average weekly bill has changed from this year to last.

As Mathews pushes her cart through aisles filled with sale tags, she is asked to clarify confusion over differences between Giant specials. The deepest savings are on half-price specials, then come Super Specials, then Bonus Specials. Fifteen percent discounts and Manufacturer Specials can be more or less savings than a Super or Bonus special. And then there are warehouse prices, which may be further reduced via any of the above specials.

Mathews said that items go on sale because of manufacturer specials; co-op ads, in which the manufacturer agrees to pay for a portion of an advertisement; or if the chain approaches an manufacturer with a deal, such as guaranteeing a certain quantity of item sales. Mathews would not divulge any of the chain's sale strategies or loss leaders, aside from this: sale products may often be featured near complementary items that the chain is likely to make a higher profit from. On this particular day, for example, cabbage, which was on sale at three pounds for 99 cents, was surrounded by bottles of specialty salad dressings that earn a decent profit margin for the chain.

As for the crucial question, does Mathews ask for paper or plastic bags, the answer is paper. They fit into her trash can.