The 3G iPhone will be free on its 35 and 45 per month tariffs from May. The 16GB version is currently only free on the 75 per month contract, while the 8GB handset is free only on the 75 and 45 per month deals.
Customers currently spend between 59 and 159 for an iPhone on the 35 and 45 monthly tariffs.
In the market for an iPhone? Here's a breakdown of all the currently shipping iPhones from Apple.