If the word auction conjures up pictures of a man with a gavel in a packed room shouting 'going, going, gone' - think again. These days governments and businesses rely on complicated online auctions to buy and sell. Auctions are also the preferred mechanism for the allocation of radio spectrum licences to mobile phone companies and the selling of mineral rights. Auctions come in a huge variety of forms, and the precise design can have a dramatic effect on the outcomes. Do you know a sealed bid from a "combinatorial clock" auction? Evan Davis and guests discuss the business of auctions. Guests include: Dan Maldoom, DotEcon Samantha Collett property developer Stephen Lerner, 3 UK Producer: Lesley McAlpine.