While it's more than certain that we are talking about entry-level phones here, it's still unclear if these ex-Android Nokias will be positioned below or on par with the existing low-end Windows Phone devices, such as the Lumia 525. Thus, an unexpected upward spike in their suggested retail price is highly unlikely.
In addition, it's pretty unclear which Nokia X devices will be refashioned to Windows Phone Lumia ones. We would wager that the recently-unveiled Nokia X2 might be spared from this upheaval. However, the original Nokia X, along with its first-gen peers, the X+ and the XL, immediately come to mind as possible candidates.
source: Microsoft via Engadget