Sony has opened up digital pre-orders for a both Knack and Warframe on the PS Store in the US.
Currently Knack is listed at $59.99, while Warframe is being offered for free since it's a F2P title.
We are presuming that the latter has been put up for pre-order so that people can download it, getting it ready to play on day one.
PlayStation 4 and both titles mentioned above arrive on November 15th in the US. Here is Europe we'll need to wait until November 29.