What is an "unlocked" wireless phone?
GSM phones use a SIM card to talk to the wireless network. When you buy a device from a wireless company, it's usually "SIM locked." This means the phone will not work on another wireless providers' network until you get a SIM unlock code from the original wireless company where the device was purchased. Some phones are sold unlocked.
How do I know if my device is unlocked?
Try borrowing a SIM card from a friend or family member who uses a different wireless company than the one the phone was purchased from. For example, if your phone came from T-Mobile, find a friend with an AT&T SIM and see if it works.
If you put that SIM card in your phone and you are able to make and receive calls, your phone should be unlocked. If you can't make or receive a call - or you get some sort of error message - then your phone is probably locked.
What can I do to get it unlocked?
If your phone is locked, check with the original wireless company where the device was purchased to get the unlock code. Different wireless companies have different policies/requirements for when and how they'll provide a SIM unlock code. Cricket can't guarantee that your phone is unlocked just because it works with another wireless company's SIM card.