What is the buy/ask spread for coins. I had a few coins that I was trying to dump and the dealer was offering me 50 cents on the dollar. Really left a bad taste in my mouth that the entire business is crooked and those dealers are just trying to take advantage of people.
It varies by the dealer and the coin. Generally the national dealers often pay better than the local ones. Finding local individuals interested in precious metals is often the best bet of all. I know individuals locally who will buy British sovereigns, German 20 marks, and most bullion coins at spot. I buy 20 marks pieces from national bullion dealers at about 3% over spot, and the sovereigns are a little more than that so if I have to sell, the price is good. They will also pay spot for the pre-1933 US gold coins.
There was a guy in the next county who had a thousand walking liberty silver half dollars, and he ran an ad in the newspaper offering them for sale at about the going rate that bullion dealers were charging. I figured he would not get that much, so I waited a week and called him thinking I could make a lower offer, but he had already sold all of them at his price to multiple buyers. So that might be another way to sell.
Decades ago when I was in the numismatic business, my markup varied, based largely on how quickly different coins would be expected to turn over, and I also had some sources, especially on pre-1871 German states coins, where I could buy substantially under market if I bought enough quantity. There were also times that I got good deals because someone else's asking price was too low, which often happened with other dealers who handled mostly US coins and were not very familiar with foreign coins.
What coins do you have that you are trying to sell?