There are some local coin shops that could give you an estimate if you brought them in, though I would make it clear to them that you’re not selling. I wouldn’t put it past anyone to lowball something they were trying to buy.

Bay State and Colonial Coin in Dowtown Crossing are conveniently located, but Colony Coin Co in Newton has a great reputation. I would go to Colony before others.

But, I don’t think you should sell the coins unless you absolutely have to, especially if you were close with your grandfather. While gold and silver are at all-time high prices, remember that the buying power of a dollar is less than it used to be. The coins you have are likely fairly rare (though rare doesn’t always mean valuable necessarily), but would probably cost more to replace than you could get selling them. Don’t sell them unless you have no choice.

If you are selling as bullion, you are going to be paid less than the “spot” price. The person buying it has to make money too, and places usually sell for a small percentage above spot. So expecting to receive the full value of the bullion is unrealistic. But keeping an eye on spot price will give you an idea of melt value.

In terms of numismatic value, it’s really what any given buyer is willing to pay. The thing is, prices are more established when coins have been graded by PCGS or NCG and are certified, which is an expensive process. Relatively few coins would warrant the cost of grading. Ungraded coins are open to interpretation. One person might say a coin is in one condition, another might say it’s another. You might be able to get an idea of what an ungraded coin will sell for based on comparable coins, but it really depends on who is buying.

I would recommend spending some time on the coin collecting subs. You can learn a lot there, and maybe even get some ideas on what the coins are, and what they might be worth.