Cellphone unlocking has gone through many trials and tribulations over the past few years. Originally, carriers used the option of SIM locks to keep tight reigns on customers by locking their phones to only work on their networks. This left customers with few options and resulted in many turning to cellphone unlocking sites and the use of various hacks.
Fortunately times have changed! Last summer, President Obama signed the Unlocking Consumer Choice and Wireless Competition Act into law. The law repealed previous rulings that had originally made it illegal for consumers to unlock their cell phones on their own. With the passage of the new law customers were given the choice, but until now, carriers haven’t been required to sell unlocked phones or honor unlock requests (although most did anyway).
According to reports from Android Police, as of February 11th, that will all be changing. CTIA-The Wireless Association which represents the international wireless telecommunications industry is laying out a set of phone unlocking (covering both SIM and network unlocking) principles that AT&T, Verizon, T-Mobile, Sprint, and US Cellular have agreed to abide by. You can view more details on CTIA's changes right here.
There are a few stipulations to having your device unlocked and each carrier has a slightly different processes and policies. First and foremost in order to have a carrier unlock your phone, you’ll need to be either paid off in full or have completed your contract term. So no you can't just go out and buy a new phone on the cheap with a two year contract and expect to be able to swindle the phone company.
Second, you may be required to pay a nominal fee. This would usually only apply if you are not a current customer. However, the report from Android Police states carriers may charge a "reasonable" fee. Third, the phone must meet all eligibility requirements which also includes not be 'blacklisted' as being stolen or having a bad IMEI.
If you want to see the full unlocking policy for each carrier, you can check the links below:
Android Police’s very thorough post on the subject. If you have any questions please feel free to comment below and we'll help you out as much as possible!