The kid is 11 years old, and he's casing the weekend Maryland flea market with all the acumen and staying power those years have brought him. He ignores the Hardy Boys mystery books at half price, ignores Civil War guns and relics, coin collections, old 45 rpm records and your basic flea-market trifles. He's looking for baseball cards. And he's got to find them first. Ahead of the four or five other kids racing around from booth to booth fueled by the rumor of last week's find of a 55-cent Brooks Robinson. It isn't always easy. "Wish I had some, sonny. Those are gettin' scarcer than hen's teeth," a dealer waxes sympathetic and points him in the direction of another booth where there may be treasure in the form of a 21/2- x 31/2-inch cardboard card smelling faintly of bubblegum dust and featuring likenesses of such higher beings as Tom Seavers, Reggie Jackson, Rich "Goose" Gossage and -- wonder of wonders -- maybe even a 1954 Ted Williams, said to be the scarcest postwar regular-issue card in existence, worth approximately $600. "My mother threw them out" may be the Portnoy's Complaint of past generations of baseball-card collectors, but no mother worth her salt today would dare touch those alphabetized and categorized hoards buried under sweatsocks or heaped on closet floors. Young would-be millionaires are learning the ways of inflation -- buying, selling and trading their way to perhaps fortunes at some future date and stacking their inflation hedges in neatly labeled shoe boxes. After all, who knows but that Howard Ruff might not someday predict that the only thing you really need to keep the wolf away from the door is a well-rounded baseball- card collection in mint condition? Take for example the 1 million cards reposing in the Metropolitan Museum of Art's Print Study Room. Although Weston Naef, curator of photographs, declines to put a value on the collection of advertising art cards donated by Jefferson R. Burdick in the early '60s, he admits it may be very valuable. Certainly the collection, the bulk of which are baseball cards, attracts "many people," says Naef, people like Burdick "passionately interested in advertising art" and willing to spend some time poring over the original albums and boxes in which they are kept. But it isn't really the money. Or the future value. It boils down to saving your childhood somehow. Trading memories of a time when baseball was the important thing. You didn't have to play to collect baseball cards; you only needed to know how to flip. You drew a line and flipped your cards from there to the wall. The closest won. You rooted for your team and traded for your favorite players. You savored the statistics on the back of each card. Batting averages, pop-ups, home runs, scores Just a few innings after baseball became America's national pastime, small cards featuring pictures of players appeared. In 1885, the first known set of baseball trading cards appeared tucked in with packs of Allen and Ginter "little cigars." In the early 1900s, small cards featuring pictures of favored players were used to stiffen packs of cigarettes. Today they appear with regularity in drugstores, supermarkets, five and dimes, in packs of six wrapped in glossy paper accompanied by a stick of pink aromatic bubblegum. All this is brought to you by Topps Chewing Gum, Inc. of Brooklyn and Duryea, Pennsylvania, said to be the largest manufacturer of bubblegum and bubblegum-related items in the world. What Bill Blass, Calvin Klein and Ralph Lauren have done for fashion, Topps has done for bubble 407-card set with pictures in brighter, sharper color. It was the beginning of variations on the same theme. With their caps on, with their caps off, holding a bat or pitching a ball, there they were, the heroes of the game: rookies, stars, coaches, managers, home-run kings, a kid's own baseball league ready to be tucked away in his room. At six-week intervals, Topps brings out six series of its cards each year for distribution throughout the country. And it's around this time of year -- just as the World Series begins and baseball mania reaches its peak -- that Topps starts making plans to assemble its new line, to appear next March along with the other first signs of spring. And as soon as the World Series ends, collectors' conventions begin springing up in motel and hotel meeting rooms across the country. That first whiff of fall air means winter is coming. Winter without baseball. Collectors need a fix. They need to trade and buy, and to meet with other collectors. Sunday afternoon at a Washington, D.C. Area Baseball Card Sports Memorabilia Show. There are cards mounted in three- ring notebooks, cards under glass, cards in sheets of plastic, cards in boxes, in albums, hung on walls. This Sunday's attendance is only 350, says Nick Shoff, who has brought this show to the area for the past four years. On Saturday, 600 people vied for spots in front of long metal tables piled high with a slice of Americana, It's a show where you can't tell the dealers from the collectors -- or the reverse. Every dealer is a collector, every collector a potential dealer. "Almost as soon as you start collecting, you're a dealer. You begin selling off your duplicates to get other cards you want. You become a dealer without even knowing it." Gary Sowatzi from Annandale is 35 years old. His hair pulled back in a ponytail, Sowatzi sits behind his collection of baseball cards spread out on the table before him. He says he collected cards when he was a kid, too, but run into a familiar problem: "I saved them, but my mother didn't." Collectors' needs are eclectic. One whole family is looking for a Carl Yastrzemski card. A lone collector is searching out Dixie lids, old covers from small ice-cream cups with pictures of players on the ice-cream side -- complaining that he's spent $30 and had to take a few lids in poor condition. Whatever a collector is looking for, some dealer is bound to have it. "I sell Mike Schmidt's underwear, Steve Carlton's jockstrap. They're $5 apiece," says Phil Spector of Randallstown. Spector is wearing glasses, a mustache, a short afro and a yellow T-shirt with black letters that say "Phil" on one side and "Happiness is a 1952 Mantle" on the other. Of course, today you would be a little less happy with that Mantle card: "It was worth $3,000. Went down to $1,500," observes Spector. The people call him "Philadelphia Phil." He moved to Maryland from Philadelphia, and his booth shows his lingering loyalty to the Flyer's hockey team. Spector collects anything related to the Flyers, "excluding peanut-butter jars with ice hockey star Bobby Clark on it." How did he become a collector and dealer? "I went to shows and fell in love with the excitement. You get hooked. You need a fix. You have to go out and buy something." When he isn't dealing in cards, Spector is a plant manager of a paper-box company, but he finds most of his friends through his hobby in nostalgia. "Eighty percent of my friends are people I met in the hobby. Even people I sold banners to send me pictures of their rooms." But Spector sees things getting tougher: "At one time I has his own story. "This is near and dear to my heart," says Stuart Hanlein, 42, of College Park. "I resisted my mother throwing them out. She got my comics, she got my model airplanes -- but she never got my baseball cards." Hanlein's story has a twist, one that has him searching with his nine-year-old son for baseball cards anew. "I made a foolish mistake," he says. "I sold under dire circumstances. A guy had to have a card to complete his collection and I didn't have a car. He offered me some terrible green stuff and I turned around and spent it on a car." Most collectors are bound together, whether they're amassing collections as a hobby or for profit, by nostalgia -- similar childhood memories, the documented facts on cards that trigger yesterday's flavor, tarot cards of warm-weather days. For some it becomes a consuming interest. Nick Shoff is 37 and his mother never threw away his baseball-card collection, which is probably only one reason he's now co-owner of the Baseball Card Sport Stop in Vienna. "I'm from New York and that was the thing there in the '50s. In the early '70s I stopped in an antique store and saw baseball cards from 1910. Then I saw this antique guide that listed prices and I saw cards I owned," says Shoff. So Shoff started going to flea markets, buying and selling. At a card show in 1975, he met his partner John Scott. "I was selling, John was buying," says Schoff. Both Schoff and Scott have regular full- time jobs: Shoff is a chemist for the Veterans Administration and Scott owns an insurance agency. But their hobby and passion is card collecting. Seven months ago they sold their original store, The House of Cards, which occupied the back room of a Wheaton bookstore, "for a good price," says Schoff. Now, in a storefront on Route 123, they have room to display their hobby and part- time business. Any Saturday from 11 to 6, people are welcome to sit in the back booth under the "Bleacher Entrance" sign and browse through the hundreds of thousands of cards that line the walls and tumble out of file drawers. "And we always have the ballgame on," says Scott, patting the television set. Scott and Shoff like to talk cards. "We like the place to be a hangout. Someplace to stop in and talk about the most recent game," says Shoff. And, if it's a slow day, Shoff, who says he'll "take anybody on in flipping" will take a challenge in the store. If you can't win cards, you can buy nearly any one you might want, out of the approximately 1 million sports cards Shoff says are in stock. Besides cards, there are game programs dating back to the early 1900s, pennants, publications such as "The Trader Speaks," "Sports Collector's Digest," "Baseball Hobby News" -- almost anything except perhaps a Honus Wagner. Honus Wagner, a star shortstop of yore, was a nonsmoker who, discovering that the Sweet Caporal cigarette company had included his picture among the cards in its packs in the early 1900s, threatened to sue. So the company withdrew all Wagner cards, making them an instant classic. If you had one today it would help a great deal toward a down payment for a condominium. "Honus Wagner was selling for $8,00 or $10,000; now it's probably worth twenty or thirty. In the early '70s I had a chance to buy it for a thousand, but that was a lot of money," recalling an if-I-had-only moment. But the dealer doesn't like to see his 10- to 18-year-old clientele in it for the money. "If he's out to invest, I'd say stay out of it. It should be fun. I think it is going to go up. But I advise against it. If he enjoys the stuff that's fine." Like hobby is stable. It is going to go up, but not the same as it was before in those super spurts. Those days are gone." GETTING CARDED THE WASHINGTON AREA BASEBALL CARD SPORTS MEMORABILIA SHOW will be held this Saturday and Sunday, 10 to 6; admission $1.50 each day. Best Western Maryland Inn, 8601 Baltimore Boulevard, College Park. Call 588-3853. IN DECEMBER: There'll be another show December 5 and 6, same hours, same admission, at the Westpark Hotel at Tysons Corner.