1960 Porsche 356 1600 Super Roadster going up on the auction block, Barrett-Jackson Classic Car Auction, Scottsdale, Ariz. Rob Levine Getting auction fever on a Golf Course at the Phoenician Resort, Phoenix, Ariz.

Auction Basics

Hugh Hildesley, Executive V.P., Sotheby's, New York

• Before bidding, assess the authenticity of the item, its condition, the house estimate and your bid limit.
  
• The "hammer price" is the final bid for an item at an auction.
  
• Auction house commission and state tax can add up to an additional 28 percent to the hammer price.
  
• Most items have reserves--the seller's minimum. Buys below the estimate are a bargain and sellers can withdraw if the reserve isn't met

Memorabilia Basics

Leila Dunbar, Sotheby's, Hollywood, Calif.

• House estimates are very interpretive, weighing many factors--movie, role, actor, and awards the movie won all figure into the estimate."
  
• Most important are the costume's screen time and current condition.
  
• Always buy what you like, but also the best condition that you can afford.

Leila Dunbar
Senior VP, Director of the Collectibles Department, Sotheby's
www.sothebys.com