Whether you buy a new phone or a used one from a reseller like SoonerSoft, at some point you're going to be deciding if you should get an unlocked phone or not. Maybe you want to switch carriers whenever you like. Perhaps you're travelling and would like to use a local pay-as-you-go provider instead of pay high international charges to your own provider.
An unlocked phone can be used with any carrier (with a few caveats, which we go into below), but usually they cost more. If you know you'll be with your carrier for a long time, buying a phone dedicated to it might be best for your budget. There are some services that can unlock your phone, too. They vary in cost, and some phones require unlocking from the carriers themselves, and some of those carriers charge extra fees while others do not.
We've gathered a few thoughts on unlocks here for you to keep in mind as you purchase.
Just a quick note before we get to phone unlocks: SIM cards can be locked, too. You can usually set up a PIN code in your preferences to set a SIM card to lock if it is removed from your phone. That way no one else can grab it, stick it in their phone, and use up all your data unless they know that code.
If the phone asks for a PIN Unlock code (PUK) when you turn it on, it usually means the SIM card has the lock on it. Don't try to guess it because the SIM will become permanently locked and unusable! Contact your carrier for help if your SIM is asking for a code you don't know.
Android phones usually require entering a long code in order to unlock it. If you put in your SIM card and the phone asks for a Device or Network Unlock code, you can enter the code provided by your unlock service and you should be all set. If you are having your carrier unlock the device, they should handle all of this for you. Some Android devices might have a separate app to run and step through unlocking.
Most phones have a limit to the number of times you can try to enter a code. Some only allow three or five tries while others allow ten. If you type the code in wrong, type slowly and carefully the next time, and keep track of the limit. Using that last try and getting it wrong will hard lock the phone. You will not be able to unlock it without special help from your carrier -- and, depending on the manufacturer, maybe it can never be unlocked!
iPhones don't require a code, but they do need network or wifi access to verify the unlock status. Apple keeps a central database of all the IMEIs. Drop in a SIM different from the carrier, and the iPhone will connect to the database and unlock itself. Some iPhones require being connected to a computer and iTunes for the unlock to complete, but most will do it fine wirelessly.
Now come the gotchas. Just because a phone is unlocked, it doesn't mean it is unlocked for everywhere. Some phones only get unlocked for their original country. For example, an unlocked Canadian iPhone may work for any carrier in Canada, but it might not be guaranteed to work in the United States or Europe.
Cell phone networks can be a big factor on whether an unlocked phone will work where you are. Some phones have both GSM and CDMA antennae, but some do not. An unlocked CDMA phone might work with Verizon or Sprint, but it won't work with AT&T or T-Mobile. GSM phones work in many more places, but even they might have different frequencies that aren't provided in your area or country.
There are even different types of "4G" or "LTE" access. We don't need to go into the technical names of the networking schemes in this little article. Just know that some phones may have faster or slower internet access for streaming music and video depending on which version of networking they have.
If you have any questions about connectivity to your carrier's voice and data networks, your best bet is to ask the place you are buying from or contact your carrier to verify details.
Don't Get Discouraged
It might seem like a lot of things to worry about, but, honestly, most phones will unlock just fine and most unlocked phones will work anywhere. These are just some things to keep in mind so you don't get frustrated when a phone might not quite work as planned. Your reseller or your carrier should be able to help you quickly, whether it be getting a phone replacement to you, fixing the one you have, or refunding you if there just is no other equivalent phone available. Don't panic! Usually you'll be on your way in no time to being able to switch carriers on your phone any time you like.