Apple announced iPhone 5S and iPhone 5C on September 10th and they revealed that both the mobiles will be available in the market from September 20th. Apple and its carriers made the pre-order for iPhone 5C available from September 13th itself, while they are not offering the pre-orders for the new iPhone 5S, which will be available in the market from September 20th (Friday 12:01 AM). You must have already read our previous post on iPhone 5S and 5C, regarding the need to upgrade as well as other details, iPhone 5S and 5C are available with following carriers AT&T, Sprint, T-Mobile and Verizon.
So, iPhone 5C is available for $99 (16 GB) with 2-year contract and also $549 (16 GB) for unlocked device. Walmart is offering exclusive discount of $20 on the iPhone 5C and 10 on iPhone 5S on the launch day Set by the Apple (Source : The Verge). Walmart also announced iPhone 5 (16GB) model which is one of the outgoing iPhone models, will also be available for $79 with 2 year contract from September 13th. Other models iPhone 4S is available for $0.97 on 2-year contract and iPhone 4 for $0.10 on 2-year contract, and I’d like to suggest you not to go with these devices, as you’ll be locked with 2-year contract for the outdated models and they also lack LTE connectivity.
Check out the official Apple site, in order to know more about the comparison and features of their devices.
As per some of the market experts, it appears that the reason for iPhone 5S, not to have the pre-order availability is because of the Supply constraint. So, with no pre-order process, it is expected that customers can start buying iPhone 5S from iStore or carriers (At&T, Verizon, Sprint, T-Mobile) or retailers (Best Buy, RadioShack and Walmart) from September 20th and the supply of the high-end device is expected to be little tight, while on the other end iPhone 5C is having really comfortable availability on supply.
As per the information provided by GottabeMobile, you can try at the RadioShack stores, as some of the stores have already started taking names, as you can consider them as the unofficial iPhone 5S Pre-orders.