International Coin Values

Same answer for both - NumisMaster, the website run by Krause Publications, the company that releases the hardcopy world coin catalogues. Click on "Find My Coin", select "world" in the origin option picklist and go from there.

This will tell you the compositions and basic stats of the coin type. For more detailed statistics (including composition), you need to register with them (which is free). Unfortunately, if you want to see mintage figures and catalogue values, you have to pay a subscription.

Don's World Coin Gallery is much easier to navigate than NumisMaster but has less info on it; it has basic statistics on the most commonly encountered coin types. He doesn't have coin compositions and only lists the catalogue value for the "most common" date/mintmark for that type; you might have a scarce date or mintmark and couldn't tell from Don's lists.

Or, you could just post your coin queries here on the forum, and we'll try our best to answer such questions for you.