My best deal was probably the Knapp-Hall, sold by a book & music dealer who used to frequent the science fiction conventions in our part of the country. They used to have a physical store as well. (Now they sell music only at cons, out of their home, except for a few leftover things from the old store.) Anyway, one time I saw this one deck sitting on the book rack, one of two copies I think, all by themselves, plainest box in the world, published by the Philosophical Research Society, and the copyright inside says 1981. It had been opened already so I could look at it, and I fell in love. I think I bought it around 1990 for about half what most decks went for then.