There are calculators online like this one that help you calculate the silver value of a collection. Some coins with key dates and good condition may fetch more, but the melt value gives the intrinsic value of the silver in the coins. They generally sell from 5% below melt value to 10% above depending on whether it is a private sale or eBay.

They can be a good way to start collecting silver because you can buy fractions of an ounce and they are easily recognisable and less worry about fakes.