I want to add, do not sell to the first coin collector that offers you a price. Though exceedingly unlikely, my mother inherited a coin that she knew was worth a lot (grandfather told her it was a special coin, in the pricing book it just had triple asterix next to it for price). The coin shop she took it to, offered her something like 500-1000 for it, and was disgruntled when she said thanks no thanks. She ended up taking it to a coin show. The first couple people she showed it to, said that they didn't deal in that coin, but to show it to so and so who would be able to buy it. That gentleman was very nice. He explained that if she wanted full price, she needed to sell it at auction, and would get 45-50K for it, depending on interest. Or, he would buy it for 35K. She ended up selling it to him and was quite a bit worried that the check would bounce until it was safely deposited.
Long story short, though it may be unethical and sleazy, there is nothing illegal about offering a really low price for something that is worth a lot more. the first step would be identifying the coins. A coin book may help. Different dates are worth different amounts. The 2nd step is to go onto ebay and see what those coins recently sold for. That will at least give you a ballpark.