The iPhone 5s is launching today in the US, Australia, Canada, China, France, Germany, Japan, Singapore and the UK. The device can be bough from Apple's own retail stores in the US with a plan for Sprint, Verizon or AT&T or from T-Mobile (although T-Mo iPhones are expected to ship between 7 and 10 business days). The cost in the US is the usual - 16GB for $199, 32 GB for $299 or 64GB...
Source: http://www.gsmarena.com/apple_iphone_5s_first_availability_wave_here_reported_low_supply-news-6825.php