NOTES FROM a columnist's cuff: Remember when clerks and salepeople had to be nice to customers, and shopping was fun? Those days are gone. On Monday, I set forth with a long list of things I wanted to buy and $160 in cash to pay for them. I came home with the $149.56 in change because salespeople didn't know, didn't care and couldn't be bothered . . . Frank L. King, executive veep of the Writing Instrument Manufacturers Association, reports that by the time the Agriculture Department's survey of coffee and instant coffee prices got in to print, it was out of date, The survey used $3.39 as the price of a 10-ounce jar of instant coffee, but Frank says that at Grand Union the other day a 10-ounce jar of Nescafe cost him $4.39 . . . Owen J. Remington says a price increase of this kind is covered by Gold's law, which teaches that whenever people discover a substitute that costs less, they create such a demand for it that the substitute becomes more costly than the thing for which it is being substituted.

IF CONGRESSMEN are given franking privileges to permit them to write to their constituents, Kathryn Thomas wonders why constituents are not given free postage when they write to their congressmen . . . Marisa Sandifer of the District of Columbia Lung Association received a call from a Southeast woman a few days ago what she could do with a dozen shopping bags filled with empty cigarette packages can be turned in to provide free time on a lung machine for a sick child. Everybody in the neighborhood had pitched in to collect great mounds of empty packages, and now Marisa had to explain to them that the whole thing is "an unconscionable ruse," because nobody trades lung machines for trash . . . If you have any books, prints or recordings you can donate to a good cause, consider calling 244-4667 for a free pickup. Your contribution will become part of the Vassar club's annual spring sale. It raises money that provides scholarships for young men and women from this year.

THERE'S AN interesting editorial in the February issue of the magazine Government Executive.In it, publisher C. W Borklund wonders why the Labor Department can't just give us the actual tally on the number of unemployed people in this country instead of engaging in "mathematical skulduggery" by making seasonal adjustments to the figures. Borklund charges that 536,000 of the unemployed in the lastest count are "pure fabrication" . . . Betty R. Everhard of Falls Church disagrees with my feeling that President Jimmy Carter ought to ease his restriction on the playing of "Ruffles and Flourishes." Betty says that making a big fuss over a chief of state might be appropriate in a monarchy, but not there. Meantime a member of the Marine Drum and Bugle Crops tells me that the President has informed the unit he will have "only one or two" White House assignments for it this year . . . Nighclub comedian Danny Klayman, who is now appearing in Miami, writes: "Swine flu hasn't arrived yet, but we'll be prepared for it. I'm already organizing a telethon for it" . . . "Hats off to our teen-aged generation," says Isabella B. Krey, a retired McKinley High School teacher. When a tire on her car went flat, David Waddell of Ijamsville, Md., came along and changed it for her . . . "Look at the upper right-hand corner of page 351 of the Maryland telephone book," Rose Marie Bryan of Silver Spring suggested.So I looked. And what I saw there was the heading, "FRENCH-FIRED" . . . Joe Griffith of Dallas asked a kindergarden lad, "What are you supposed to do when you get sick?" And back came the reply, "Insult a doctor" . . . Clyde Moore of the Columbus (O.) Dispatch doesn't mind setting his thermoistat down to 55 overnight but comments, "There is a slight problem in the morning - shaving with mittens on."