Update (09/17/18): The iPhone 6s was discontinued on September 12, 2018. You can still purchase it through some third party resellers. Pricing varies.
Pricing for the iPhone 6s varies depending on the carrier and plan you select. Here are the available options and pricing plans for the iPhone 6s.
Colors: Silver, Gold, Space Gray, Rose Gold
Storage: 16GB, 64GB, 128GB
Carriers: AT&T, T-Mobile, Verizon Wireless, Sprint