''I spend about half of what most people do by buying in bulk through the co-op and doing without things we like - like ice cream,'' says Cheri Loveless, mother of five and co-author, with Barbara Salsbury, of ''Cut Your Grocery Bills in Half!'' (Acropolis Books, Washington, D.C., 1983).
''But Barbara spends even less than I do - and buys things like Nestle's Quick, Cheerios, and steak. It's amazing.''
Mrs. Salsbury, a consumer advocate in Utah who teaches ''supermarket survival'' courses, says she feeds her family of four adults on ''about $100 a month.'' But she spent even less in 1975, when her husband went back to school and the family lived on royalties from Mrs. Salsbury's books - less than $5,000.
''That's when I learned to intensify my comparison-shopping skills,'' she says.
Five years ago on a lecture circuit, she met Mrs. Loveless, a Virginian who happens to be the daughter of investigative reporter Jack Anderson. Together, they poured Mrs. Salsbury's skills into a book that mixes heavy accusations with practical advice.
The accusations are aimed directly at grocers, who, according to Mrs. Salsbury, trade on their customers' tendency to buy on impulse.
''Two-thirds of every dollar spent at the grocery store is a store decision - not your decision,'' she says. ''You have to get up before breakfast and stay awake to keep ahead of the grocers.''
This attitude has brought her trouble from the Utah Retail Grocers Association, who were instrumental in stopping Mrs. Salsbury's seminar on grocery shopping at Brigham Young University, she says.
James Olsen, president of the association, says Mrs. Salsbury was ''downgrading specific products, which is against university policy.''
Mrs. Salsbury says she bases her accusations on seven years of reading trade magazines and learning their methods.
She says retail grocers are advised to:
* Set up impulse-buy items - such as cookies, sodas, ''specials'' on paper towels - on the aisles closest to the check-out counters.
* Put the more expensive items at eye level on shelves, with cheaper items stored where the consumer must bend or reach to get them.
Mr. Olsen says eye level is the spot for ''higher-volume products - why should the customer have to reach for a popular item?''
* Compare their prices with competitors. Often, Mrs. Salsbury has found, these comparisons are made between two different week's prices, or between their ''special'' price and a competitor's ''regular'' price.
* Run ads for spectacular prices on a product, but - in fine print - limit the consumer to one or two items of that product and require a $7.50 minimum purchase to take advantage of the buy.
* Give the store an ''inexpensive'' image - with metal shelving, items still in boxes, and large banners - while reducing prices on produce and milk, ''because most shoppers keep those prices in their heads. Then they get their profits from staples - cereals, rice, sugar.''
* Run ads for ''specials'' on items that are sold for only a few pennies less than usual.
Mrs. Loveless shows this graphically in a week's grocery ads. ''You see, this store has a special on detergent for $1.79,'' she says. ''But just turn the page - this other store has the same brand for $1.39. It's amazing how obvious it is, once you know how to look.''
Mrs. Salsbury spends one-half hour each week scrutinizing newspaper and mail ads - another hour and a half driving to ''two or three different stores,'' including drugstores and department stores for paper and soap products.
She buys in bulk, storing it in her basement, her pantry, and her two freezers. ''I have a garden, so one freezer is for that,'' she said.
Because she has been using this method for a long time, she doesn't need to get more than milk and produce weekly, buying specials at her leisure.
''Last week, there wasn't a thing worth buying,'' she said. ''But this week, they're having a special on pork, so I'll buy maybe $12 worth of pork.
''Another store has a good deal on cake mixes, ice cream, and cabbage at 9 cents per pound, so I'll probably spend another $8 there.''
Doesn't she think all this watching the ads and driving is a bit difficult for the average working woman? ''She's the one who really ought to look out,'' Mrs. Salsbury says.
''The big push in the grocery business now,'' she says, ''is toward that working woman, putting out all this propaganda that she doesn't have any time and therefore should buy expensive convenience foods. That just frosts me.''
The shopper with limited time can ''save right off if she just understands the store layout'' and steers carefully past the impulse-buying sections, Mrs. Salsbury says. ''She can also save a bundle by using house brands, which are often canned by exactly the same people who put out national brands.
''And if she'll stock up on the items she usually buys whenever they're on sale - even if it's only six cans of soup instead of one - she'll save pennies and quarters that will mount up to dollars.''
For those willing to put time into her system, Mrs. Salsbury suggests spending a few weeks just getting to know prices of the items they usually buy.
When you feel familiar with prices, she says, start to look through the ads, writing down any items that interest you and their prices. If you see a good price - 10 to 20 percent less than usual - circle that item.
Then, she suggests that you spend about two months stocking up.
''Divide your grocery money,'' she says. ''Let's say that you have $100 to spend for two weeks' groceries.Figure out the absolute minimum amount of food you can get by on for those two weeks and how much it will cost - say, $60. Then spend the remaining $40 stocking up on specials.''
After a period - Mrs. Salsbury says two months, Mrs. Loveless says six - you should get to the point where your pantry and freezer can carry you, and you are only buying specials.
The hitch here is that it takes time, an afternoon each week, Mrs. Salsbury says - to read the ads and shop around at different stores.
Also, you have to change your habits and learn to cook what you have, not buy what you want to cook.
You have to work with what's available and see what you can make out of it.