In general no. Prices fluctuate up and down and therefore the best "free" version you can get is http://www.worldcoingallery.com/ Otherwise if you are willing to pay a few dollars has it's online catalogue here http://www.numismaster.com which is way too expensive in my opinion. Or alternatively, get a second hand copy of Krause or just check the completed listing in ebay.
Just in case there's anyone out there who doesn't know better, rickyb is pulling your leg. There are NO world gold coins, and very few - if any - world silver coins that aren't worth considerably more than a buck apiece. The copper, bronze, aluminum, brass, bimetallic and other non-precious metal coins range in value from a few cents to thousands of dollars!
Sure, if you want a hoard of 1967 British pennies and worthless French Francs. Find me a 1696 Crown for that price.