Well I don't have my red book with me, but I looked on PCGS prices, granted yours arn't slabbed, but it can give you an idea of the value. PCGS has this:
MS60 MS63 MS64
1950-D 13 15 17
1950-D FS 15 18 35
My guess is that they are MS60 and he is going to make his markup.
Now the question is does the coins have FS (full steps).
If you have bought from him before, he could be giving you a deal on some MS63's. I used to buy a lot of coins a few years ago from my local coin shop, I always got a better price than he had listed. Also when I had to sell some coins, he always gave me alittle more (cutting into his profit) for the price.
When I was in high school I got my first job just so I could buy a Double Eagle coin. He had a 30 day lay away policy but he let me have my coin on layaway for 3 months. I have had good experience with coinshops and bad, one place that I went to, to buy a coin that I talked with them and agreed on a price on the phone, only to have them raise the price once I got there. Remember though, they are in business to make money, know what you want and how much the coin is worth, but also expect to pay a markup.