On 2012-11-16 auctions on the National Bank of Poland has been finished and issue's prices was established for coins commemorating Piotr Michałowski.

Silver coin with the denomination 20 zł:
 - Reserve gross price: 185 pln
 - Selling price (price of issue): 185 pln
 - The number of coins to sell: 25.500 pcs
 - Total emission: 30.000 pcs
 - Auction starting date: 12-11-2012 08:00
 - Auction ending date: 15-11-2012 13:00
 - Date of issue: 28-11-2012

28-11-2012 is a day of issue coin with the denomination 2 zł and total mintage of 800.000 pieces.