April 14, Tax filing eve. So, you're off to mail the income-tax return, a day or two early and, as usual, a few dollars short. Still, it's either done or postponed with the proper forms, and that's cause for improverished celebration.

What better weekend for paupers to try to live like kings than income-tax time? A fitting time to track down the free and the cheap until the refund arrives. Let us proceed.

Friday until 2 p.m. - and FREE - the Bureau of Engraving and Printing will let you drool as your government presses tax dollars into service, churning out the crisp, green (taxable) denominations of the future. Fresh, new ones, fives, tens, twenties, fifties, hundreds hot off the presses. A good tour for the masochist.

As for the rest of you suffering from just plain taxitis, well, go on a penny hunt, shore up, take stock, sniff for sales, feel guilty. Cut up the credit cards.

Of course, there's the standard fare; free concerts, wide-open parksM art galleries, museums. Street-corner samples. Salvation Army paperbacks for a dime. The Towpath. Window-shopping. Carousing the countryside with a cheap bottle of wine.

Or try some creative freeloading; it can fill the stomach while it feeds the soul.

If you're brazen and expect to be broke, why not drop by Fran O'Brien's at 6 p.m., when the FREE roast beef, ham, rolls and condiments are expected to miraculously appear, as they do Monday through Friday, for bar customers in a back room at 1823 L Street NW? You can drink more and eat less. Or, shamelessly, order water and construct several Dagwoods. Most evenings, it takes barely half an hour for the piranhas to pick the carcass.

Of course, Fran may appear at any moment. And Fran is VERY large. He once played football. For the Redskins. Not that he would SAY anything. Fran is friendly. But nothing moves you along a buffet line like an ex-crusher who has gone without a tackle for a time.

"Oh, uh, hi, Fran!"

Fear, yes, and shame have chased a few out O'Brien's back door, down an alley, past the rat-tat-tat of jackhammers gauging for progress, and into the cool darkness of Mr. Day-s Saloon. There, also, it is possible to test the patience of the establishment by dining mightily on 10 cent hotdogs (6 to 8 p.m., Monday through Friday), hogging the bargain pinball machines (two games for 25 cents) and burping into the night.

Times are tough.

So tough, in fact, that manager Bobby Lee, gold chains jingling against a jungle of chest hair, may curse you down the block. Feint like O.J. - you've lost him - and vanish into what seems to be the basement of a bank at 1100 17th St. NW, but is in fact. The Meeting Place, a restaurant-bar whose tables (Monday through Friday, 5 to 8:30) groan under the FREE (like Fran's) buffet.

Roast beef, ham, bologns, salami, cheese of Swiss, American and cheddar nationalities, pickles, pumpernickles and rye. The spread, heh-heh, sits near the door, convenient for prideless ones to scarf and run.Nibble & Nosh

Who was it that said there is no such thing as the free lunch? Or breakfast? If you must flee the scence before eating your fill, there are other possibilities for penniless repast.

Visit the Kitchen Bazaar at 4455 Connecticut Avenue NW, where on Saturday (12:30 to 4:30) a local professor of Italian culinary arts, one Mario Cardullo, is scheduled to demonstrate his pasts. At the Falls Church branch, another chef, a crepist, will be creating crepes for the tasting. Woody's and Bloomingdales are also known to allow browsers a free nibble. Let inhibition be your only guide.

And there are always the conventions. This weekend is bounteous for such commerce hereabouts. And conventioneers can be so cordial, hosting hospitality suites full of stuff to nosh or setting out pots of coffee in the halls.

A smile, a friendly word, a firm grip can go a long way in procuring a bite here, a munch there. No telling what you might find if, on your wander, you were to pass through the Mayflower (Daughters of Colonial Wars there through Sunday), or the Sheraton Park (the Boy Scouts of America under tent there this weekend). And there are women bankers, skin doctors and private eyes gathering to yak at the Hyatt Regency.

You may even succeed where two dozen failed last year - to eat every morsel of the Zebra Room's three-foot pizza in one hour. And get the $18 meal FREE.

"They usually give up a few pieces short," says the owner. "One fella ate the whole thing two months ago. He was thin." Twinkle While You Wait

Trek over to the Washington Monument and hope there's a long line for the free elevator (tuckets available, 8 a.m. to midnight). You can play the waiting game and become a star!

Just wander over to the Reflecting Pool, where director Milos Forman and camera will be looking for up to 2,500 blue-jeaned extras to cavort about Saturday morning (clothes on, please) for the movie version of "Hair." Right on, for the Age of Aquarius. And if you tire of hanging loose, let the sun shine in while comedian Robert Klein and singer Melba Moore enterain between takes.

The Lincoln and Jefferson Memorials, of course, don't cost a dime. And the White House tour (10 to 2) is free. The Smithsonian stays open 10 to 6 daily. And - who knows? - the cherry blossoms may still be in bloom. So much history for free.

Toss a Frisbee on the Ellipse.

If you tire of walking, stop by Hains Point in East Potomac Park and cast for dinner. Base love worms.

Or cast a little further and seek a debtor's solace. Cisit the home of a colonial dirt farmer - when poor was po' and body heat alone warmed the outhouse.

That's the notion behind the 20-acre Turkey Run farm, a working Park Service flashback to the 1700s that grows pumpkins, beans, watermelons squash and tobacco. A blacksmith shoes the horses. A smokehouse cures the ham. A resident ranger cooks, plows and hands out FREE samples (10 to 4:30 daily, except Mondays). Take the George Washington Parkway, exit hear Route 123 to run right into the past. It's on the Record

All this driving for bargains is bound to wear out the tires, so keep off the treads and entertain yourself closer to home.

Take a FREE lesson of Swahili, Sanskrit, Polish or Portuguese. Danish, Swedish, Ukraninian, Romanian. Bengali, Thai or Chinese. English as a second language. The cassettes are free at the Martin Luther King Public Library. And if you own property, live, work or attend school in the DIstrict, you can take them home. Live cheap, learn cheap.

Boogie cheap. Take home Stevie Wonder from the library's collection of pop, classical, folk and jazz records and tapes.

Dylan Thomas, Robert Frost, Carl Sandburg or e.e. cummings will spout their poetry at your place, a la cassette. Or if the tax jaws have chomped severely of the flesh, play this library tape twice: "How to Conquer Discouragemnet." Bring your own recorder.

If you don't own a library card, just find a quiet corner of your favorite bookstore and digest - FREE - the latest prescription for what ails.

Learn to avoid lawyers, write your own will, wangle a raise, master the metric system, get yours, get rich and powerful, get yours, get theirs, get rich and powerful, get UP the organization.

Learn how to start and run 101 businesses for less than $1,000 down, make $1 million in the stock market, avoid saying "Yes!" when you want to say "No!" What to say after you say "Hello."

Be the person you were meant to be, avoid alimony, doctors, debt. Fix the car, the dish-washer, sink, disposal. Mend your fence, your marriage, your kids, your head.

Look RICH, feel RICH, act RICH, when you are broke as a bum. Scrooge at Home

Shop the stores that indulge your Scrooge. For discount suits, compare prices with the nearest Joseph A. Bank Clothiers, or saunter over to Arlington's The Back Door for women's cut-rate sportswear, or down the road for reduced strollers at Baby Products.

Nothing soothes the spirit like getting a deal. There are dozens of cut-rate outlets and mill stores. Good deals abound. And many are listed in "The Factory Outlet Shopping Guide" ($2.95). Or persue a paperback guide to freebies, "1001 Valuable. Things You Can Get Free" (Bantam, $1.95). Inside, you will learn how, for another 35 cents, you can send away for more FREE advice on how to stop children's wanton spending. Say "NO!" and mean it to the six-year-old who can't live another day without the R2-D2 doll.

Okay, so the kids don't exactly cozy up to your New Frugality. So don't tell them it's free, and take them to "Sing for Your Supper," a hand-puppet comedy after the fashion of France's traditional Guignol theater, at the Renwick Gallery (Friday at noon, Saturday and Sunday at 3). Or there's Bob Brown's Marionettes at Kennedy Centre for kids, kindergarten through sixth grade (Saturday 10:30 and 12:30, free tickets a half-hour before showtime), or the Washington International Competition for Pianists (Saturday at noon, in the concert hall). Rolls, Rolls, Rolls a Royce

And, if the family is fretting that Pop is headed for the poor house, well, lie. You just might buy a Rolls-Royce.

"Nyah, nyah, nyah . . ."

Okay, cool the jive and pack them over to McNey Motors in Bethesda. Salesman Charlie Harmel, who sold a fistful of Rollses last year, will likely treat you royally, as he hasn't figured out yet whom to treat like a prince and whom to treat like a serf.

"You just can't judge a book by its cover in this business," he says. "If a customer says, 'Bring it out, I want to drive it, we'll do it.Our clientele wants personalized service. We go to great lengths to meet their demands. Some parents send the kids out, and within a few days come in and buy the car."

And so, peasants, that means you just might get to wheel about in $56,000 worth of car. Stick your head out the window to convince neighbors all is well, a maneuver that may frazzle the hair - but so what?

A pittance will get it redone at the Washington, D.C. Beauty Academy, where budding cosmetologists are itching to take your head in hand on a walk-in, no-appointment basis. Shampoo, cut and blow dry, $6.50, or try the works - all that plus a facial, make-up job, manicure, pedicure and other doodads, $20 to $25. The bargain, supervised by licensed snippers, is available daily until 7:30 (Saturday 9 to 3 downtown or at three suburban locations). Counter Point

Afterwards, eat with the elite in Georgtown at the Little Tavern on Wisconsin Avenue, where a generation has dined on chef Jim Rocko's 30-cent gourmet burgers.

"Petit or grand?"

Nice try, wrong language. Rocky's assisant, Frank ("old enough to know better") Foss asks an Italian visistor, attired in mink and diamonds, if she wants the little burger or the big burger.

"Beeeeg one," she says, plopping down a Gucci bag and a small boy.

She gazes about, at signs asking customers to pay when served (no one does), giving assurance of sterilized silver (it sparkles) and generally touting the quality of beef in the burgers (she and the boy devour two each).

The check comes to $2.87.

"Good morneeeng," she says and 13 cents tinkle to the counter.

Frank, with polite, perhaps even cosmic, detachment, sweeps up the tin with the crumbs. Nary a dent in his cheer.

For dessert, it's off to Crumpets, a skip away, and day-old eclairs for a quarter, or doughnuts for 13 cents. Gourmet dining on spare change. Flowers, Like New, Almost

Poverty goes better with flowers.

And if you happen to be hanging around the back door of Johnson's Flower Center (4020 Wisconsin Avenue NW), you should inquire into the morning heave-ho of roses, carnations, gladiolas and the like. (Sunday morning, 8:30 to 9, is the anointed toss-out time.) If they've been cleaned out, cruise the trash cans of other florists. Worst they can say is no free posies.

Pack yourself a poverty picnic with day-old bread and some survival food - peanut butter, saltines, breakfast bars - and go on down to Union Station, where Jacqueline Onassis, The New Yorker's Brendan Gill and others are supposed to arrive on a "Landmark Express," scheduled for 2 o'clock, to stir up support for saving Grand Central Station. Why Washington? Well, the case is before the Supreme Court... The Late, Late, Late Show

Next onward to the main post office, practically next door at North Capital Street and Massachusetts Avenue NE, where you can hoot and howl (FREE) at deadline filers rushing to slip returns under the (April 17 deadline) midnight wire. The mood is usually jubilant, with taxpayers driving by, thrusting fat envelopes at mailmen who hustle about like carhops. Inside, you might even make a few friends by advising procrastinators on their last-minute deductions.

So what if Uncle Sam's a louse. Somebody still loves ya, baby.