It all depends on where you are flying from and when. Different airlines charge different prices. So contact different airlines or a travel agent and tell them where you want to fly from, And they...
A Jetstar one-way flight for one adult would cost 119AUD departing at 9:10AM on the morning of 23/06/2010
56 Hours
a average price for going from say NJ to Florida is around a little more than $ 200 for 3 people
This question cannot be answered because you did not say where you are STARTING from.