The cost of an iPhone will depend on where you are buying it from. This map here shows prices across the globe. You'll certainly not want to buy it the places marked with the color red.

Mobile Unlocked put together the interactive map. You can see prices country-by-country in US dollars.

The map however isn't a very fair comparison, since there are things to consider like carrier subsidies, exchange rates and more. You definitely don't want to buy an iPhone in Turkey though.

[via ​Forbes]