I have a friend who is in charge of part of an estate consisting of coins that have to be sold. I want to be fair to him but also be able to purchase as many coins as possible. I know a dealer would offer 40-60% of value. What percentage would you offer? I also know the price his dad paid for most of these coins.
This is a very difficult question to answer. Bottom-feeders pretty much want to know what the coins would melt for. Average buyers want to know what the dates, mintmarks and grades of the coins are. High buyers want to know everything the average buyer does, and want to know the quality of the coin being offered, understanding that quality and grade are often unrelated. This can seldom be conveyed electronically, and normally requires an examination in person. For some underrated issues, you might be very surprised to learn that some specialty dealers might pay a lot more than what the market perceives the value to be.
When doing business, leave any relationships out of it. Offer a fair price for fair coins. If you offer more, you're gifting him money (hey, if you want to do that, go ahead), if you offer less, you're stealing from him (which, again, is your choice). This is absolutely impossible to say. What is your goal with these coins? Are you going to be keeping them as part of your collection? I would say that you should then pay a fair retail price for them. Are you going to be reselling them with the intention of profit? Decide what reasonable profit you desire, and then make an offer based on that (and be clear that this is your intention). Absolutely irrelevant, especially if the coins were bought a long time ago. Any price you negotiate needs to be based on current market prices. Sure, he might have bought that $20 Saint for $25 a few decades ago. You know what it is worth today - and you have to use today's value in any calculations.