Although dealers are free to fix their prices, there are tremendous differences between same coins of same quality. How comes ? Interesting to watch and compare ! On this example, Judean coin from AgrippaII, from $.260 to $.1250...
Check out the link below...Besides condition and devices the legend can have a ton to say about why some coins are far more valued than others... I hope @dougsmit can find a moment to elaborate. https://www.acsearch.info/search.html?id=1214603
You never know who will show up at which sale. I paid $200 for a coin I wanted the other week but now I have it, would I pay $200 for another one? Would you or will someone get it for $100 because they were the only bidder that day? Do you see the coins in the OP as equal in every way? I would pay no more than $10 for either one but I don't collect those and have no idea if there is a difference that explains this or not. Generally when a coin goes for way more than usual it just means that it was wanted by two people with enough money that they did not care how much they paid. The old story is that the 'Third Known' coin failed to sell because there were only two people who cared and they each already had one.
-what intended to refer to is sellers/dealers'pricelists, not auctions where the highest bid depends on the need of bidder - sometimes purely arbitrary - is to ensure to win a coin "at any cost"..
There are probably as many reasons as there are possibilities. Some hope to maximize profit or simply require larger profit margins due to high purchase prices or other high costs of business. Some offer ridiculous listings apparently hoping the novice collector will consider it a 'fair market price' and grossly overpay for a coin. Most of these dealers inevitably end up with surplus stock unsold for months on end. Those that offer competitive prices for the grade/condition ultimately are the most successful since it is a simple task to compare prevailing market prices with what is being offered at any given time.
I agree that what a coin (or cast bronze item like a bar) brings at auction is a function of what the second high bidder is willing to pay. If only one person wants the piece, the price is closer to the opening bid, or the lot is unsold. The dealer, or auctioneer, must find a price to get the bidding started. If the auction house is lucky, two or more want the same item. Coins of Julius Caesar bring a good price not because of their rarity, but because lots of people want them. I have been looking for a couple of years for a coin with a plumb bob. When one came to auction this year, I paid much more than for other examples of the same coin.
