If you are ready to just pick up your suitcase, take a look at the budget travel website later today. They have some good last minute deals popping up!
Krakow is a lovely city and it's VERY cheap. I was there last year for 3 nights. Booked flights with Ryanair for E50 return. Hotel was 2 minutes from the main square and cost E70 pn. Food was very high standard and very reasonable. I actually brought money home!