The Gold Coin Buyer - Specializes in purchasing U.S. coins. Includes a FAQ and sample prices. - http://www.goldcoinbuyer.com/
National Gold Exchange - NGE buys and sells rare gold coins, silver dollars, and bullion. Generic gold including St. Gaudens double eagles, Liberty double eagles, Indian eagles, and others. - http://www.ngegold.com
Centennial Precious Metals - Products available for your personal investment portfolio include gold bullion and semi-numismatic (pre-1933) gold coins; also silver and platinum. - http://www.usagold.com/
Douglas Winter Numismatics - Buying and selling rare U.S. gold coins struck in the 18th and 19th centuries. - http://www.raregoldcoins.com/