The iPhone 5 is not offered for free since no cell phone carrier sells the iPhone 5, as of 2013. Apple ceased production of the iPhone 5 in 2013 and replaced it with the iPhone 5s and the iPhone 5c.
Initially, Apple told cell phone providers that the iPhone 4s would remain as a free option for carriers if their subscribers wish to take a two-year plan. After the launch of the iPhone 6 in 2014, the iPhone 4s was discontinued and replaced with the iPhone 5c as the free option. Some cell phone carriers do not offer it for free, but rather charge $1 plus sales tax for the two-year contract.