A puck just went for 81 dollars on EBay... I've never tried it, but there's no way that it's worth that much...
You can sometimes get lucky and pick one up for $35. Also look for vintage Wrisley or Paislays, which are purported to be rebranded Yardley.
Great point! I bought a puck of vintage Wrisleys and it shaves just as well...doesn't smell as nice, I think it was kept in Satan's armpit for the last 50 years...but it shaves like a dream