hello i have sprint and i want to upgrade my phone to a htc evo 4g help!!?

[Ulyses]

hello i have sprint service and i want to upgrade to a htc evo 4g and i have a 2 year contract my contract started in October 6 2010 and i know a year is not pass but how much does it cost to just upgrade without the contract deals or eligibility like i want to buy it in whole and also do you still have to buy the data plan if your phone has wifi.. please help thanks