Ethics At A Local Coin Shop?

The store clerk was lying to get her to sell....Even if its her fault she doesn't know the value of something its not the point. If he offered $8 a coin then just said this is all I can offer you and kept his mouth shut then fine. But he went ahead and claimed these coins are out of favor with collectors trying to sway her decision by stating false opinions making her believe they arent worth as much and she wont do better at other places.

Not really connected, but also a recent story about ethics and a local coin shop...

This Monday, I wanted to visit a local coin place in the morning, before going to university (where I had classes in the early evening).
However, I was busier that morning than I expected, and wasn't able to go outside until 3pm or so, which didn't leave me anywhere near enough time to visit the coin shop I wanted to see (I hope to get there tomorrow, actually, but this is a bit tangential to the story).
So I went to the Taganka open-air coin market, which was close enough to being right on the way between me and university (unlike the one I originally intended, which was half an hour the other way) that I needed a lot less free time to be able to get there.

Upon arrival to Taganka, I saw about four dealers, one of which was pretty clearly packing up and wasn't willing to sell me anything. My repeated questions of "where's the bargain bin" got me pointed to Vitalik (though I didn't know his name yet), who had three big bags labeled 20, 30 and 50 rubles (roughly 25, 40 and 65 US cents respectively).
I stayed for a few minutes going throgh the 20 ruble bag. Ultimately, I chose 14 coins (that's a total of 280 rubles, or $3.50), and asked Vitalik for an empty ziploc bag to put the coins in (while I'd be going through the 30 ruble bag). He went through his pockets, and didn't find any. No regular polyethylene bags either.
So he just put them in one of his pockets. Um, why not, I thought, it's a bit unusual for a temporary place, but he's going to be taking them out anyway. (Note that at this point I hadn't paid for anything yet.)
I went on to the 30 ruble bag, went through it for a few minutes as well, and chose 9 coins, for a total of 270 rubles, or $3.60 (the mismatch is because the dollar values were crudely rounded by me, but basically the total was roughly the same).
He gives me a ziploc bag this time (no idea where he got it). I say, well, 270 plus 280 is 550 rubles (at this point I take 550 rubles out of my wallet and into my hand), now give me the other 14 coins from your pocket please?

I never actually saw these 14 coins. What I got instead was a rambling speech that was about 80 percent (maybe more, I hadn't counted) assorted obscenities.
I had heard of people talking in pretty much straight obscenities. I never expected that I would ever meet one, never mind a coin dealer.
I tried my best to figure out the content of his speech (most of the obscenities seemed to be just random interjections); as far as I could tell, he was proposing that I should go and visit a prostitute, and that we should compare our penises.
(For the record, he used the obscene word for penis, and I'm not sure I correctly interpreted the prostitute part, which was also described obscenely.)
I very politely answered that I wasn't particularly interested in the former, and that I definitely wasn't interested in the latter, and in any case the weather was all wrong for that (it was snowing).
[Incidentally, I think that's about the fourth coin dealer who told me that he wanted me to go visit a prostitute. (Though the first three had, for the most part, managed to keep that proposal fairly polite and free of gratitious obscenities.) I have no idea why.]
My repeated queries as to the first 14 coins were met with slightly varying repetitions of mostly the same thing, with the occasional request not to talk nonsense (as if what I was saying was any more nonsensical than their own ramblings) or approval that I was sober (which I was - I almost never drink alcohol, and as far as I know had never actually been drunk - but there was no further mention as to what my sober status meant, only more obscenities).

However, as I noticed that the other 9 coins (which I had in my hand) had not been mentioned either, I decided that the dealer forgot about them, and after yet another tirade of assorted obscenities, left without paying (taking the 9 coins from the 30 ruble bag with me).
I was quite unsure that I was correct to do this, though, so on my way out, I came to one of the other dealer and said "I wonder if the other guy noticed that I didn't pay him".
So the other dealer said "Vita-alik! Did you get the money?" and Vitalik answered "Yes!" (that was when I found out what his name was) and the other guy said "Oh, that's fine then" and I left.
I still wonder if I was anywhere remotely near ethical not to pay the surprisingly foul-mouthed guy any money.

The coins were quite nice, incidentally (though perhaps not as nice as the other 14 coins that I didn't manage to get - that lost bunch included, among other things, an 1919 Wheat cent, one of the 1950s Romanian types I wanted, and some Japanese aluminium and tin coins from the 1940s).

I'd have offered her more money, straight up in front of the dealer. He was basically robbing her.