Some Target retailers in North America are selling Knack on the PS4 for only $39.99.
This is $20 cheaper than the standard RPP of $59.99. This might be a pricing error, although some people managed to still get the game for that cheap price. Unless of course the price is correct to attract more parents to buy a PS4 and Knack for their kids.
Knack and the PS4 will be released on November 15th in North America. If you want to buy the game this week, check out Target first to see if you can score yourself a bargain.