You can have a fair idea of the value of your coins, if you can compare it with other coins with prices in stores. Sometimes the latest coin auctions will give you the current prices. But do not use the price if the coin is not of the same condition or grade. You may also look around coin stores for their asking prices as they usually update their values. You just ask them how much will they pay you for a similar coin (add their selling price and buying price and divide to get the average). Although, this is not always correct, at least you have an idea of values. You also have to ask collectors and dealers, for verification.