Rosebud, the sled made for Orson Welles's classic 1941 film ''Citizen Kane,'' was bought Wednesday afternoon by Steven Spielberg, the director-producer, for $55,000 at Sotheby Park Bernet.

The addition of the 10 percent buyer's fee made the total price $60,500.

The sled, one of three balsa versions made for the final scene of the movie, is the only one that survived the filming. The other two were burned in filming a scene in which a workman tosses the sled into a furnace.

Describing ''Citizen Kane'' as ''the most classic movie ever made,'' Mr. Spielberg, who bid by telephone from Los Angeles, said the sled was ''a symbolic emblem of quality in the film business.''