Yahoo Auctions

Offers various categories to buy and sell.
http://auctions.yahoo.com/

QXL

Online auction with offers for European consumers, including arts, collectibles, cars, computing, consumer electronics and entertainment.
http://www.qxl.com/

eBay

International person to person auction site, with products sorted into categories.
http://www.ebay.com/

uBid

On-line auction house.
http://www.ubid.com

Amazon.com Auctions

Organized by category with search available. Also lists some items for Sotheby's.
http://s1.amazon.com/exec/varzea/subst/home/home.html

The Free Auction

Offering a wide variety of categories. Includes live chat and message board.
http://www.thefreeauction.com

Internet Auction

Offers a items for auction divided into categories.
http://www.internetauction.net/

Steal it Back

Police auction selling seized, repossessed, and confiscated items on online auction.
http://www.stealitback.com

YNotBid

General auctions online.
http://www.ynotbid.com

InterAuct

Singapore auction site.
http://www.interauct.com.sg/

Trade Me

Free online auctions and classifieds for New Zealanders.
http://www.trademe.co.nz/

Tradehall

Trade a variety of items.
http://www.tradehall.com/

SalvageSale, Inc.

Claims recovery and commercial salvage.
http://www.salvagesale.com

Auction4it.com

Includes electronics, jewelry and household items.
http://www.auction4it.com

Auction-Warehouse

Name-brand computers, peripherals, games, and electronics.
http://www.auction-warehouse.com

CQout

Wide variety of products including arts, books, fashion, housewears and jewelry.
http://www.cqout.com

General Services Administration Auctions

U.S. government offers the general public the opportunity to bid electronically on a wide array of federal assets. Surplus, seized and forfeited assets are available for bidding.
https://www.gsaauctions.gov/

Auctionweiser Enterprises

Includes price guides, listing fees, and FAQ.
http://www.intershopzone.com

Epier.com

Toys, collectibles, electronics, real estate and apparel listings.
http://www.epier.com/

Bid4Assets

Offering jewelry, real estate, and personal property.
http://www.bid4assets.com/

Utrove.com

Computers, automotive, housewares, music and electronics. Includes a gallery and account information.
http://utrove.com

Bidz.com

Includes jewelry, antiques, art, coins, autos and electronics.
http://web-1.bidz.com/

Bid Monkey

Includes books, electronics, coins, and computers.
http://www.bidmonkey.com/

Auction & Barter

Books, clothing, beauty, collectibles, home and garden.
http://www.auctionandbarter.com/

Romahawk

Includes jewelry, music, collectibles, video games and personal care.
http://romahawk.com

Bidville Auctions

Offering a wide variety of products, includes a watchlist and image gallery.
http://bidville.com

Christian-Auctions.com

Includes bibles, books, music, computers, and collectibles.
http://christian-auctions.com

Sam's Club

Includes apparel, electronics, computers and software, jewelry, and toys.
http://auctions.samsclub.com/

KaBid.com

Products offered include books, coins, stamps, trading cards, sporting goods, toys, and music.
http://www.kabid.com

Bid-Alot.com

Offering listings for a wide variety of products. Includes information regarding photo uploads and registration.
http://www.bid-alot.com

Auction Fire

Offers a variety of categories. Includes image hosting, consignment service, message board and fraud alerts.
http://auctionfire.com/

Vintage Auctions of Canada Ltd.

Online auctions for collector cars, art, and other items.
http://www.VintageAuctions.ca/

iOffer.com

Offers electonics, crafts, business, hobbies, home and garden, video games and computers.
http://www.ioffer.com/

Tradeaway

Find, sell, trade, barter, buy any new/used item, service or real estate.
http://www.tradeaway.com/

eBid

No fee online auctions with items sorted by category.
http://www.ebid.tv/

Bidera

General merchandise sorted by category. Proxy bidding and bulk item uploading.
http://www.bidera.com/