What is the cheapest and best way to travel from Berlin to Krakow?

I am traveling from Berlin to Krakow this summer and I have found very inconvenient, expensive ways of getting between the two cities but I feel there has to be an easier way. Any suggestions on the most efficient (night trains etc) and cheapest way to travel to Krakow from Berlin? Thanks!|||A $80 single way air ticket from Berlin to Krakow is kind of acceptable, about one hour flight with Air Berlin, what do you think?