If you can identify the country, date and denomination of the coin, type those details into the
NGC world coin database search line. It will give you the prices as per the Krause world coin catalogue. Note that the values given there are retail prices, what a collector could reasonably expect to pay. If you were selling the coins to a coin dealer, you'd expect to get a lot less than that.
If you're having trouble identifying them, post pics in the ID Required section. If you're unsure of the condition of your coins and want grading opinions, post them in the relevant Grading section.
If you want a formal valuation, for insurance purposes for example, you'll need to take your collection to a coin dealer or professional valuer and get it properly valued. The opinions of an anonymous Internet crowd aren't going to cut it with your insurance company.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis