Froogle:
Developed by Google, Inc. One of the most promising price comparison sites to date.
BizRate:
One of the largest price search sites. Over 30 million products listed.
Shopping.com:
Child of Dealtime and Epinions, now merged to provide you with three shopping search engines that feature your products separately, yet the same.
Yahoo Shopping:
Complete Yahoo Shopping data feed creation and maintenance solutions.
MSN Shopping:
Complete MSN Shopping data feed creation and maintenance solutions.
NexTag Shopping:
Complete NexTag data feed creation and maintenance solutions.
PriceGrabber Shopping:
Complete PriceGrabber data feed creation and maintenance solutions.
Robert Matthews Coin Authentication
Specialises in the scientific examination and authentication of British milled coins.
Professional Coin Grading Service
Includes prices and descriptions of grading and authentication services.
ANACS
A service that renders an opinion on a coin's authenticity and grade.
ASA Accugrade, Inc.
Devoted to the education and protection of the consumer since 1984.
Numismatic Guaranty Corporation of America
Submit most US and world coins for grading through an authorized member/dealer.