I have no miles on Northwest other than the trip that I took last week from DCA-MSP and back. I flew on full Y fares. I was able to upgrade each way on the day of the flight for $50 on what they called a WorldPerks upgrade. On the first leg they ended up not even charging me.

While I'm no fan of Northwest from a previous bad experience, I must say that being able to upgrade for a nominal fee was pretty nice considering my complete lack of status. In otherwords, Northwest is pretty generous with its upgrades compared to some.