Galaxy S3 is free in the u.k on contract with the three network. You also get unlimited (truly unlimited) data , 3000 minutes and 5k text messages. Its about �30 a month for the contract.
Same contract with a iphone 5 is �70 for the handset then �30 a month after that. Iphone 4s/4 are available for free on three network. Dont know about usa prices .