Bidding box for home-played games. Use of bidding boxes has several advantages over oral bidding: it reduces noise in the room, prevents bidding being overheard at neighboring tables, allows easier review of the auction, and reduces the opportunity to pass unauthorized information to one's partner (intentionally or not) by the manner and intonation in which one makes one's bid. A bidding box is typically a plastic box with two slots, each containing a set of bidding cards. One slot contains 35 cards with symbols of bids (5 denominations—clubs (), diamonds (), hearts (), spades (), and notrump (NT)—in seven levels of bidding,
Bidding fee auction MadBid, one such site, called this model "a license to print money." By contrast in an article on Madbid, The Guardian (28 January 2012) comments "legions of penny auction sites have folded, including Swoopo, Rapid Bargain and Bid Boogie." Due to the possibility of participants spending a lot of money and still losing an auction, or ultimately spending more than the retail value of the item they end up winning, some analysts have criticized the model or compared it to gambling, even when operating without fraud. The Better Business Bureau warns consumers, "although not all penny auction sites are scams,