Since there's no statute of limitations here, one of my better and more unusual dealings from the late 70's:
As a kid I collected just about everything (comics, cards, coins, stamps, records, etc) because back then you could find deals like this at flea markets. Kid had a beer-case of baseball cards and they looked pretty good, so I asked him how much they were: "fifty cents" was his reply, and I was really unsure if that was each or all. If it was each I was sunk, as there were about 500 cards and I was about 12 years old at the time. So I asked him, "each?" He must have had no idea, and been taken aback by my question (apparently I come across as pretty harsh/aggressive, even though I don't mean to be) so he just said "Ok, $2 for the box." I quickly gave him the two bucks and walked the box back to my grandmother's car, the whole time some other dealer really pestering me to resell the box to him. After about ten "f -off's" he finally got the message.
Oh, and the cards? All mid-1950's Topps in excellent condition, all 500 of them. Multiples of Aaron, Williams, Mays, Clemente, Campanella, etc. One of my better hauls.