Reverse Auctions, or Penny Auctions as they're now often known as, are a way of allowing players to buy items for a few pence, as opposed to the asking price. The aim is to make the lowest unique bid - the person who does that in the allocated time wins the reverse auction and gets the prize for the bid price.
Auctions tend to have bid limits (the number of bids made in each auction) and time limits. Players can usually bid more than once, but it costs a fixed amount to enter each time. Entry is either via online payment or SMS credit depending on the game.
You can currently take part in reverse auctions online at Madbid - many other sites have fallen by the way side - which might give you an idea of their popularity. Prizes include cars, holidays, iPhones and plasma TVs. People do win (well all the sites have winners lists) - but check out the Madbid video below to see information about their Mini Cooper car winner.
Remember if you bid early there's a greater chance that your bid will be repeated by another player, so it won't be unique. Bid late and there's a chance you'll be making non-unique bids and therefore costing you more to play. According to Million21, who now run reverse auctions for selected brands, the most popular bids are round numbers (20p, 100p) followed by numbers ending in 5 (e.g 25p, 75p). The best advice is to look at other results and see where the winners pitch their bids at.
