You can purchase unlocked iPhone directly from Apple; but if you have a limited budget, the subsidized iPhone sold by carriers will be the better choice.
However, that means your iPhone will be locked (here is Metro PCS) and is not able to use with different SIM cards if needed, even though you purchase it bundled with a two-year contract from one of the mobile operators that carry it (here is Metro PCS carrier)
The carriers may not want you to unlock your device, but there are several instances which you may need to do it, especially if you travel a lot to different markets or if you want to sell your iPhone.
If you are finding a service provider to unlock your iPhone from Metro PCS, we're the best choice for you.
We, iPhoneIMEI.net, are proud of the best service provider in the market. We are always willing to take care of your iPhone by unlocking it via official way with the cheapest price. Moreover, we ensure 100% money-back guarantee if your iPhone is not unlocked. You just have to pay a very nominal fee to unlock your HTC locked Cellcom network. Besides, we also accept payment via PayPal, which is secure and reliable.
About Metro PCS carrier
MetroPCS (stylized as metroPCS) is a prepaid wireless service in the United States that is part of T-Mobile US, Inc.. MetroPCS provides nationwide talk, text, and data depending on the plan services using GSM, HSPA, HSPA+ and 4G LTE networks. MetroPCS previously operated the sixth largest mobile telecommunications network in the United States using code division multiple access (CDMA) technology. The legacy MetroPCS CDMA network has been decommissioned on June 21, 2015. Its legacy 4G network using LTE will be integrated with T-Mobile US' own 4G LTE network. (By Wikipedia)
How to unlock Metro PCS iPhone?
Step 1: Find your IMEI number. You can dial *#06# and then locate your IMEI (or open Settings > General > About > IMEI to see the IMEI number)
Step 2: Visit iPhoneIMEI.net, click on the Unlock iPhone button at the topbar, then select Metro PCS USA from the network list
Step 3: Enter your IMEI number and choose your iPhone model, then click on “Unlock now!” button, then it will take you to a checkout page
Step 4: Here, enter your billing information along with your email address. Once you are done, an email will be sent to your email address in minutes (the email with subject: “Congratulations, your iPhone has been unlocked”)
Step 5: Now just simply connect your iPhone to Wifi or a computer with Apple iTunes installed, your iPhone will be unlocked automatically