The most popular sites in all 'Shopping' categories, according to the Alexa Toolbar. Updated daily.
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1.
International person to person auction site, with products sorted into categories.
www.ebay.com
Site info for ebay.com 
2.
Amazon.com seeks to be Earth's most customer-centric company, where customers can find and discover anything they might want to buy online, and endeavors to offer its customers the lowest possible prices. Site has numerous personalization features and services including one-click buying, extensive customer and editorial product reviews, gift registries, gift certificates, wish lists, restaurant and movie listings, travel, and photo processing.
amazon.com
Site info for amazon.com 
3.
Provides a wide array of electronics, apparel, baby, sports, toys and fitness. Includes a store finder and blog.
www.walmart.com
Site info for walmart.com 
4.
Online retailer of books, video games, toys, music, and video recordings. Region 2 DVDs and prices in pounds sterling.
amazon.co.uk
Site info for amazon.co.uk 
5.
Trend-forward merchandise at this national discount retailer.
www.target.com
Site info for target.com 
See top sites in all 'Shopping' categories