In Germany it became a official memorial day in 1996; in 2005 the United Nations picked that date too. Today 27 Jan is observed in a dozen countries; some others have different dates, others do not. As for the price the seller wants - ouch. I could offer a plastic ballpoint pen and expect people to pay two million euro, dollars, pounds ...

Do you know who issued that medal?
(Edit) Five years later, Poland issued several coins that commemorated the liberation of Auschwitz and Birkenau. See
this brochure (PDF, English).
Christian