PsychoAuction is a very small penny auction site. PsychoAuction auctions last 5 minutes.

Pardoo is a small Penny Auction site. In addition to the usual Penny Auctions, Pardoo offers Fixed Price Auctions (pay only the auction price regardless of the level the bidding reaches) and 100% off auctions (winning bidder does not have to pay the final price, only shipping).

Bidso is a small United States based View Price or Reveal Price auction.  Bidso allows you to earn bids by filling out various offers from their partners, similar to the offer wall in a lot of Facebook games like Mafia Wars.

BidHere is an Australia based Penny Auction site. BidHere offers a wide variety of auction features, such as Cash Back, Speed and $0 auctions.

BidRivals is a global Penny Auction site, with dedicated sites in over 20 countries. BidRivals has a wide assortment of auction items, offering many features, such as Buy It Now and Use Lost Bids.

Swoopo is one of the best known Penny Auction sites. Started in Germany in 2005, Swoopo has expanded worldwide to the United States as well as South Korea. Swoopo has a very large selection of items and features attracting a large number of users from all around the world. Enter promotion code fb0374 to get 3 free bids at registration.