SIM-free iPhone 6 and 6 Plus units have been available in Europe since last year, but now US-based Apple fans can grab one too. If you want to avoid carrier plans - and subsidies - you'll have to shell out $650 for a 16GB Apple iPhone 6. The iPhone 6 Plus starts at $750. Note that there's an T-Mobile uncarrier version for the same price but you don't have to get it if you truly want no carrier strings attached to your phone. Anyway, you know the formula - each storage bump is $100, making the top of the line 128GB iPhone 6 $850 and the iPhone 6 Plus with the same storage...
Source: http://www.gsmarena.com/iphone_6_and_6_plus_now_available_simfree_in_the_us-news-10664.php
