I Got A Great Deal On A 1967 50 Cent Coin At A Pawn Shop

(I know this is really long, sorry about that)
Today I decided to go to a pawn shop and see if they had any coins. The guy there had silver in a pile he was selling for melt value.
In the pile I saw this centennial 50 cent and asked the price. He pulled out a calculator and said "it's 40% silver so $5 (The 1967 50 cent coin is 80% silver so actual melt value is $10 )". He didn't seem to know that much about other Canadian stuff either as he was also under the impression that a bunch of other post 1964 Canadian coins were also 40% silver (they are all 80% except for some 1967 dimes and quarters and all silver 1968 coins which are 50%!
He said that whatever doesn't sell is going to get melted. Among other common dates, he had a whole bag of centennial dimes as well as some george V quarters. (one 1909, two dateless) I am planning on going back to save some more Canadian "40%" silver from the smelter when I have more spending money (college is expensive). I know they are only worth melt, but it still kills me that "common" coins, some in fairly good shape, are being destroyed. I'm glad I could save this from the melting pot!
One piece of advice for pawn shop shopping is know the value of what you are buying. The same place that sold me the 50 cent coin at half of melt value had some other coins that were really overpriced.