How did the LEGO Duck become a classic icon?
I sent the question to LEGO customer support and they replied:


  The LEGO Duck became a classic icon because it was the first LEGO toy
  ever to be released.
  
  We do not have any lists of where would sell this product however I
  imagine it would be sold at some antique markets or antique shows so
  keep a look out!
  
  We do not have any idea for how much it is worth as it is priceless in
  our eyes and not sold by LEGO any longer. It also does not have a set
  number which may be why it is hard to find on the internet.