For a potential investor, the appeal of buying into sports collectibles can be enticing and nostalgic, but at the same time undeniably perilous.

Recent evidence points toward a growing market. Dealers in sports items across the country say they are selling more complete sets of Topps baseball cards than ever before."They were definitely our biggest seller last Christmas," said Pat Quinn, 48, owner of the Sports Collectors' Store in the Chicago suburb of LaGrange, Ill.

"Our mailing list grows with every show we sponsor," said John Blasco, 23, of Buena Park, Calif., a transplanted New Yorker and full-time coordinator of baseball card conventions.

"We ran one show out of a hotel in Boston last August, with 90 some-odd dealers," Blasco said. "We drew almost 4,000 people one day and the fire department had to close the show down for an hour, the crowd was so huge."

But therein lies the catch. The potential for astronomical profit in any collectible, whether in sporting goods or works of art, is determined by its rarity.

So experts say that anyone making bulk purchases of contemporary Topps baseball cards would be better off investing money elsewhere, if investment is indeed the primary motive.

"You'd better be very careful of what you are buying," said Larry Fritsch, 52, who has collected bubble gum cards of every sort since 1948, and whose collection is so comprehensive that one percent of it is sufficient to house a card museum near baseball's Hall of Fame in Cooperstown, N.Y.

Fritsch is also considered the first man to make a business out of selling and trading baseball cards. He opened his dealership in Stevens Point, Wis. in 1970, and has heard every opinion about collecting.

"It's a relatively new hobby, and subject to fluctuations," Fritsch said. "But I would not want to compare sports collecting to gold and silver, because they have a market beyond collectibles. I prefer to look at card collecting as a hobby, not an investment."