An increasing number of Americans are pursuing the hobby of collecting for both fun and profit. Contrary to what your mother told you, allowances used for "junk," such as comic books and baseball cards, may have been money well spent. In fact, your old lunch pail could result in a big sale.

-Lunch boxes. Scott Bruce, a 33-year-old visual artist, has earned the title of "Mr. Lunch Box" by parlaying a couple of junk shop finds into a collectible monopoly. His collection now includes more than 1,500 lunch pails. Some of his favorites have pictures of Trigger (Roy Roger's horse, of course), Land of the Giants and The Man From U.N.C.L.E. television series."Lunch boxes reflect the entire television landscape from the fities and sixties," Bruce said. "The baby boomers grew up around the boob-tube, so there's a lot of nostalgia involved in collecting lunch boxes."

Until four years ago, lunch boxes were plentiful and cheap. More than 120 million lunch boxes were produced between 1950 and 1970, adorned with everything from Captain Kangaroo to the Beatles. One of the first lunch boxes Bruce found featured the television cartoon family The Jetsons. He bought the box for 50 cents, but it's now worth about $250.

Bruce's Lunch Box: The 50s and 60s, recently published by Chronicle Books of San Francisco, is an illustrated look at the history of lunch boxes and is priced at $14.95. Bruce also is the author of the Official Price Guide to Lunch Box Collectibles, which exhibits much of Bruce's personal collection and is available from Random House for $9.95.

If you're just beginning, Mr. Lunch Box said that rarity alone does not necessarily mean a lunch-box gem. More likely, a rare lunch box combined with a popular figure is the best investment.

-Baseball cards. Baseball cards have been part of growing up in America since the late 1800s, when tobacco companies first introduced them to boost sales.

"There is a sense of nostalgia surrounding baseball cards," said Paul Kelly, editor of The 1989 Baseball Cards and The Complete Book of 1989 Baseball Cards. "They remind us of our childhood and the great history behind the game."

Higher priced cards usually involve the baseball greats. Howver, even among the greats, there's a wide price disparity depending on the specific baseball card. A Mickey Mantle card can sell for anywhere between $75 to $6,000, depending on its condition, age and rarity.

You may want to invest in the cards of players who had foul ball careers, but garnered fame in sports commentary, such as a Joe Garagiola card (priced from $35 to $70) or a Bob Ueker rookie card ($90).

Most baseball card collectors and dealers agree your best bets may involve mistakes or variations. However, Kelly said, "investors have to remember the card company has to first correct any errors." Then it's purely a matter of supply and demand that determines appreciation.

For instance, recently printed cards of Baltimore Orioles' Billy Ripken displayed a particular four-letter word on his bat. When the variation was caught and corrected by the manufacturer, these cards were selling for around $100. But since 30,000 of the originals had already been sold, the price quickly fell to $30.

At 45 cents a shot, a novice may want to speculate on this year's roster of rookie cards as future collectibles. Depending on the player, a 45-cent rookie card could double in price within the next two years, then level off to an annual increase of 15 percent.

Hot rookie picks for this year include Gary Sheffield of the Milwaukee Brewers and Gregg Jeffries of the New York Mets. Both rookie cards are currently priced by collectors at around $5, but you may get lucky and find one in a 45 cent pack this summer. Kelly said a good year for both players could raise the price to between $15 and $20.

-Comic Books. Before television, there were comic books, which date back to the 1890s.

"Comic book collectors have either recently gained interest in a particular comic book series or in some way are reliving their childhood," said Bill Krucek of Yesterday, a memorabilia store in Chicago.

Krucek said that a good portion of comic book collectors are in their mid-20s. This group is collecting such fairly recent items as Harvey Comics from the sixties with Caspar "the Friendly Ghost" and Richie Rich. First issues of these comic books run between $100 to $400.

Of course, the highest prices involve the oldest and best known comic characters.