Score At Show, But Odd Encounter With Dealer

I went to a large three day coin show over the weekend. It's one of those shows that so big, I think I could spend the entire three days and still not see and get everything that I want to. Unfortunately, I could only spend four hours on Friday and four on Saturday. On Friday I was going from table to table while trying to force myself to keep up a good pace. I came across a dealer who had a Thomas Jefferson Coinage and Currency Set on the table. The packaging looked somewhat ragged, but I remembered that I need the special nickel for my collection. I didn't immediately remember what the going rate on ebay was, but I asked him for the price anyway. He said $12. After a brief delay while I looked at it, he said "that's below bid". He also pointed out that there's a $2 bill in the set. Although I didn't remember what they normally sell for, given that it has a Jefferson dollar, the nickel I need and the $2 bill, the price had to be good. So, I bought it. Right after I bought it, the dealer then says "Now I'm going to put the good one out." I was kind of taken aback as it was almost like he was implying that he pulled one over on me. I asked how much he wanted for that one and he said $14. I then went on to look at some other tables.

On my way home it dawned on me that I thought the Jefferson dollar must be silver because all commemorative dollars are silver. Then I thought, it must be clad because if it's silver, then it's worth the $12 in melt value alone. I took a look at it and sure enough, it's silver. So now I'm thinking that the dealer made a mistake.
On Saturday I couldn't go back until the afternoon. I figured that the other set would be sold by then, but I'd point out to him that he sold me a set for less than the melt value.

So I get there on Saturday afternoon and immediately go to his table. Sure enough the better condition Jefferson Coinage and Currency Set is still there. In fact, there's a Millennium Coinage and Currency Set right above it. So I ask him again how much he wants for the Jefferson set. He says $14. I say what about the Millennium set. He says $16 or $28 for both. At this point I'm just dumbfounded. Is there something wrong with this guy? The melt value of the Silver Eagle is worth $16+ alone. I look around at his tables. He's obviously been a dealer for a while as he as a good bit of stuff. It's quality stuff too with many slabbed coins. I chatted with him for a few minutes. No indications that he has Alzheimer's or is not otherwise completely there. The odd thing too is that he seemed so definite about the prices when he gave them to me. Many dealers have to look prices up which is understandable considering they can't remember everything. So, I bought both sets for $28.

Reflecting back now, I just don't know what to think. This is not a cherry picking situation where I found a variety that the dealer didn't know he had. Were these out of his personal collection and he based the price on what he paid? Did he buy them from someone else cheap and then just mark them up a few bucks? I sort of feel guilty like I took advantage of the guy by buying them, but then again it's his business to know the current market prices. Mentally he for sure seemed to be all there, so I really just don't know what to think. One things for sure, I certainly won't forget where I got these sets and how much I paid for them.