There are two parts to this. First is how I operate and why I do it that way. The second is a tip to sellers.
When presented with material from a seller, I review it and I offer my best price up front. Unless I made a mistake or overlooked something, I don’t normally budge from my offer. Why do I do this? It’s rooted in a past experience.
Many years ago (long before I was a dealer myself), I was at a stamp show. I was sitting at the table looking through some US stamps for my collection. A seller approached with a small album. The dealer looked at it for a few minutes and made an offer. I don’t remember what the offer was. It was obvious that the seller inherited the collection or something because they didn’t know what they had. The seller accepted the offer and walked away with some cash.
The dealer quietly turned to the dealer at the table next to him and said, “I thought he was going to counter with a higher price. But he took my offer. I really made out this time!” He didn’t know that I overheard him. I only had a few stamps picked out that I was going to buy. I put them back, walked away, and never bought another thing from him. In my opinion, he was wrong. He took advantage of the unknowledgeable seller by starting very low and he was happy to vastly underpay him for the material. I didn’t want to do business with someone who was happy to make a low offer and walk away with a small jackpot.
I don’t operate like that. I don’t want to start low and risk having a seller say, “Sure,” and I buy their stamps at a ridiculously low price. It’s not professional. I live by my principles to treat people fairly. Nor do I want to say, “Well, I was expecting you to negotiate. My real offer is this. I need to pay you more money.” I’d look like an absolute idiot.
If you sell material to me, you’ll get my best offer up front which is meant to be a fair offer. If you think I made a mistake, let’s talk about it and if I did overlook something, then I’ll revise my offer accordingly.
As a seller, especially if you’re knowledgeable, you should be able to ask a dealer how they arrived at their offer. No one is going to go stamp by stamp and say, “This one is 50 cents. That one is $19.85.” A dealer should be able to tell you, “In general, the condition looks like this. The market for these items is down right now.” In a few minutes, a dealer should be able to defend their offer. Whether you agree with their analysis or not is an entirely different matter.
If you’re a knowledgeable collector and you have some idea of what your material is worth and what you would like to sell it for, you don’t need any further advice from me. You and the dealer can hammer out a deal.
If you’re not knowledgeable about what you have (e.g., you inherited a collection), then I suggest two things for you.
First of all, if it’s possible, try and find out what you have. This is easier said than done – especially if you’re dealing with older material where varieties exist and there is a wide range of prices. In these cases, it’s probably safest to assume you always have the cheap variety (most folks don’t have the expensive one – that’s why it’s expensive to begin with!). But if you have something more ordinary like, say, a box of 500 First Day Covers from the 1970s and 1980s, then you can probably find someo online dealers or auction sites. What are they selling similar material at? Is it $50? $200? More?
If you really have no clue what you have, then I suggest that you always counter with a higher offer. See what the dealer says. If it’s me, I’ll tell you that you already have my best offer. You can decide to accept it or not. Other dealers may negotiate a little. It’s worth a try.
I also suggest soliciting several offers. You don’t have to accept the first offer. Yes, it is more work to solicit multiple offers, but in the end, you can sleep better knowing that you probably got a fair price.
If three dealers all offer about $100 for your material, then you have something worth about $100. You can decide which offer to accept. If one dealer offers $100 and two other dealers offer $1000, then clearly you should take the $1000 offer. The dealer with a low offer is either corrupt (sorry folks, that does happen!) or they made a mistake or overlooked something.