The Numismatic Guaranty Corporation maintains the World Coin Price Guide, a website that offers detailed information about coin values free to the public. Local libraries also often maintain subscriptions to research tools, such as Numismaster.com, an online version of Krause Publications' "Standard Catalog of World Coins."
The World Coin Price Guide offers a database that includes coins from 1600 to the present day. Users search by entering a coin description or browsing by country and denomination. Browsing also allows selection of further criteria such as region, date, catalog initials, and catalog number. The website also includes links to a tutorial and the Numismatic Guaranty Corporation's U.S. Coin Price Guide.