Apple is rumored to bring two new iPhones this year. This never happened before. It sounds though very reasonable that Apple is introducing in 2013 a new lower cost iPhone along the high-end iPhone 5S to reach new markets. Earlier this year Apple fans hoped that a new iPhone would come before summer. Now everything definitely points towards September.
The Wall Street Journal reports that Apple has contracted Pegatron to be the primarily maker of the low-cost iPhone aka iPhone 5S mini (adopting a naming scheme from Samsung). Apple Insider has a report up that says that the supply chain is getting ready to produce parts for the iPhone 5S.
As reported earlier the new iPhone 5S might have an integrated fingerprint sensor and no physical home button. This would allow for a complete smooth glass surface with only a speaker hole. If true this design could be a major visual difference to the iPhone 5S mini. The iPhone 5S mini is also supposed to have a plastic case to lower cost.