For 4.5 days and 4 nights, here is our cost breakdown:
€132 :: Accommodation
€130 :: Date Night, Foods, Drinks
€37 :: Tours, Entrance Fees
€85 :: Transport (Metro, Overnight Train)
In USD,with current exchange rate of $1.35, that equals out to $518.50. Wowza!
Per person, per day that equals out to $57.61, which is surprisingly less than one might think. You can do Berlin much cheaper especially when it comes to food.