Possible Clues:

• You may bid on it
• Auction site that explicitly forbids the selling of souls
• PayPal's parent, once
• Place to do your bidding?
• Web site with a 'Buy It Now' option
• Website whose logo's letters are (in order) red, blue, yellow and green
• Shopping website
• One of its first customers was a collector of broken laser pointers
• Cybermarket since 1995
• PayPal's former parent