How much does it cost to repair s3 cracked screen?

if go third party stall i tin about 500

Alright..usually will they be able to repair on the spot or I will have to leave my phone with them?

takes few hours time .. it all dpending on if ur phone still have warranty ongoing , if there is , then i tin its better u go to samsung service center , more xpensiv by about rm100 but it keeps the warranty going