Possible Clues:

• Weird Al song that wonders, 'Tell me why I bid on Shatner's old toupee'
• Website where you can shop by category
• 24-7 auction site
• Where Warren Buffett sells an annual lunch date for charity
• Site with a Guaranteed Delivery program
• Company whose Nasdaq symbol is its name
• Where the meaning of life was sold in 2000 for $3.26
• Website with a 'Buy It Now' option
• Where the original Hollywood Sign was sold
• Site with a 'can't sell' list