Apple is leaving no option untouched to attract its customers. From providing a colorful family of iPhone 5c to three different shades of iPhone 5s, the company is now offering iPhone 5s that comes "unlocked" or "SIM-free" for those who don't like to be tied down by a 2-year contract.

Earlier when you bought iPhone 5s from Apple online stores, strings came attached in form of a two-year deal. But the new offering from Apple has no strings attached. However, it comes at a higher price - whereas the price of iPhone 5s with 2-year contract started at $199 (16GB), the unlocked/SIM-free version starts at $649. The 32GB retails for $749 and the 64GB goes for $849.

All that's required for the SIM-free iPhone 5s is a GSM-compatible SIM. It means AT&T and T-Mobile (as well as any GSM carrier worldwide) will be supported, but if you're a Sprint or Verizon or any CDMA fan, you're out of luck.

If you choose the T-Mobile variant, the iPhone 5s will be shipped with T-Mobile SIM card already installed and you'll need to activate it in an Apple store or T-Mobile store. On the other hand, if you choose the carrier-free, SIM-free flavor, the iPhone 5s will be shipped without any nano-SIM. It means you'll need to get the nano-SIM from any GSM carrier before you can start using it. "To start using your iPhone, simply insert the SIM card into the slot and turn on iPhone by pressing and holding the On/Off button for a few seconds. Then follow the onscreen instructions to set up your iPhone," Apple said.  

Interestingly, there is a subtle difference in the time taken for the delivery of "T-Mobile" and "SIM-free" iPhone 5s. According to Apple, it will take just 3-5 days if you opt for the unlocked T-Mobile version whereas for a carrier-free, SIM-free iPhone 5s, you'll have to wait for 1-2 weeks. 

iPhone 5c has been available in both subsidized and SIM-free flavors since its launch.